news

한어Русский языкEnglishFrançaisIndonesianSanskrit日本語DeutschPortuguêsΕλληνικάespañolItalianoSuomalainenLatina

today, the semiconductor industry is in a critical period of transformation. the semiconductor field dominated by silicon is facing bottlenecks such as high power density, high frequency, high temperature, and high radiation. the third-generation semiconductors have emerged, and the development of new materials represented by gan and sic has driven power devices to move towards high power, miniaturization, integration, and multi-functions. however, key characteristics such as heat dissipation and energy efficiency are still the industry's unswerving pursuit.

in an era of pursuit of ultimate performance and efficiency, a chip revolution led by diamond is quietly emerging.

diamond refers to the rough diamond that has not been polished. so, as a new semiconductor material that has entered everyone's sight, what is the charm of the "diamond" chip? behind the infinite possibilities, progress and challenges coexist.

what is the charm of “diamond” chips?

diamond, known as "the hardest substance in nature", is not only incredibly hard, but also has excellent thermal conductivity, extremely high electron mobility, multiple excellent performance parameters such as high voltage resistance, large radio frequency, low cost, high temperature resistance, and other excellent physical properties.

specifically, diamond semiconductors have material properties such as ultra-wide bandgap (5.45ev), high breakdown field strength (10mv/cm), high carrier saturation drift velocity, high thermal conductivity (2000w/m·k), and excellent device quality factor (johnson, keyes, baliga). diamond substrates can be used to develop high-temperature, high-frequency, high-power, and radiation-resistant electronic devices, overcoming technical bottlenecks such as the "self-heating effect" and "avalanche breakdown" of the devices.

in addition, diamond has excellent physical properties. in the optical field, it has good light transmittance and refractive index, making it suitable for the research and development of optoelectronic devices. in terms of electricity, its insulation properties and dielectric constant enable it to play a stabilizing role in complex circuits. in terms of mechanical properties, its high strength and wear resistance ensure that the chip can withstand extreme working conditions.

these characteristics make diamond show great potential in the field of chip manufacturing, and it is often used for heat dissipation of high-power density and high-frequency electronic devices. it plays an important role in the development of 5g/6g communications, microwave/millimeter wave integrated circuits, detection and sensing. diamond semiconductors are considered to be a promising new semiconductor material and are hailed as the "ultimate semiconductor material" by the industry.

by using diamond electronics, not only are the thermal management needs of traditional semiconductors alleviated, but these devices are more energy efficient and can withstand higher breakdown voltages and harsh environments.

for example, in electric vehicles, diamond-based power electronics can achieve more efficient power conversion, extend battery life, and shorten charging time; in the telecommunications field, especially in the deployment of 5g and higher-level networks, there is a growing demand for high-frequency and high-power devices. single-crystal diamond substrates provide the necessary thermal management and frequency performance to support next-generation communication systems, including rf switches, amplifiers, and transmitters; in the consumer electronics field, single-crystal diamond substrates can promote the development of smaller, faster, and more efficient components for smartphones, laptops, and wearable devices, thereby bringing new product innovations and improving the overall performance of the consumer electronics market.

according to data from market research firm virtuemarket, the global diamond semiconductor substrate market is valued at $151 million in 2023 and is expected to reach $342 million by the end of 2030. the forecast compound annual growth rate from 2024 to 2030 is 12.3%. driven by the growing demand from the electronics and semiconductor industries in countries such as china, japan and south korea, the asia-pacific region is expected to dominate the diamond semiconductor substrate market, accounting for more than 40% of global revenue share by 2023.

driven by its characteristic advantages and broad prospects, diamond has shown great potential and value in many links of the semiconductor industry chain. from heat sinks, packaging to micro-nano processing, to bdd electrodes and quantum technology applications, diamond is gradually penetrating into various key areas of the semiconductor industry, promoting technological innovation and industrial upgrading.

heat sink and heat dissipation:diamond has become the first choice for high-power heat dissipation due to its excellent thermal conductivity and insulation properties. the thermal conductivity of diamond single crystal heat sink is 5 times that of copper and silver. in semiconductor lasers, diamond heat sinks significantly improve heat dissipation, reduce thermal resistance, increase output power, and extend life.

this characteristic makes diamond have broad application prospects in high-power igbt modules in new energy vehicles, industrial control and other fields, helping to achieve more efficient heat dissipation and higher power density.

at present, the heat sink material commonly used in high-power semiconductor lasers is aluminum nitride heat sink, which is sintered on a copper heat sink as a transition heat sink. however, when the thermal conductivity is required to be between 1000 and 2000 w/m·k, diamond is currently the first choice or even the only available heat sink material. there are two main forms of diamond used as a heat sink material, namely diamond film and diamond composited with metals such as copper and aluminum.

semiconductor packaging substrate:the substrate is the key link in heat conduction in bare chip packaging. al2o3 ceramics are currently the most produced and widely used ceramic substrates, but due to its thermal expansion coefficient (7.2×10^-6/℃) and dielectric constant (9.7) are relatively high compared to si single crystal, and thermal conductivity (15-35w/ (m·k)) is still not high enough, resulting in al2o3 ceramic substrates being unsuitable for use in high-frequency, high-power, and ultra-large-scale integrated circuits.

therefore, with the development of microelectronics technology, high-density assembly and miniaturization characteristics are becoming more and more obvious, the heat flux density of components is getting larger and larger, and the requirements for new substrate materials are getting higher and higher. the development of substrate materials with high thermal conductivity and better performance has become a general trend. as a result, high thermal conductivity ceramic substrate materials such as aln, si3n4, sic, and diamond have gradually entered the market.

among them, diamond has gradually become the focus of attention for the new generation of packaging substrate materials due to its high thermal conductivity, low thermal expansion coefficient and good stability. diamond/metal matrix composite materials prepared by combining diamond particles with high thermal conductivity metal matrices such as ag, cu, and al have initially demonstrated their great potential in the field of electronic packaging.

although it is not easy to make a single diamond into a packaging material and the cost is relatively high, its thermal conductivity is dozens or even hundreds of times better than other ceramic substrate materials, which has attracted many large manufacturers to invest in research. especially at a time when computing power demand is surging, diamond packaging substrates provide innovative solutions to the heat dissipation problem of high-performance chips, helping the rapid development of industries such as ai and data centers.

micro-nano processing:third-generation semiconductor materials such as silicon carbide and gallium nitride are difficult to process, but diamond powder and its products have become cutting-edge processing tools due to their super-hard properties.

for example, diamond tools play a key role in the cutting, grinding and polishing of silicon carbide crystals. in addition, with the popularization of technologies such as 5g and the internet of things, the demand for precision machining in the consumer electronics industry is increasing. diamond tools and micro-powder products provide high-quality precision surface treatment solutions for metals, ceramics and brittle materials, promoting technological progress and industrial upgrading in the industry.

in addition, diamond has advantages in many fields such as optical windows, bdd electrodes, quantum technology, etc., and is regarded as a strong competitor for future semiconductor materials.

the industrialization of "diamond" chips continues to progress

at present, the world is stepping up the research and development of diamond in the semiconductor field.

element six wins uwbgs project

recently, element six is ​​leading a key project in the united states - developing ultra-wideband high-power semiconductors using single crystal (sc) diamond substrates. the project is part of the ultra-wide bandgap semiconductor (uwbgs) program led by the u.s. defense advanced research projects agency (darpa), which aims to develop the next generation of advanced semiconductor technology for defense and commercial applications, breaking through the performance and efficiency limits of semiconductors.

although the prepared large-size diamond wafers can be used in heat sinks and optical fields, there are many difficulties in commercial application in the field of electronic-grade semiconductors. for example, the technical problems of synthesis, stripping and grinding and polishing of large-size single-crystal diamonds need to be further solved.

to this end, element six has established strategic partnerships with several key players in the semiconductor industry, including hiqute diamond in france, orbray in japan, raytheon, and stanford and princeton universities in the u.s. these collaborations integrate expertise in crystal dislocation engineering, rf gan technology, and surface and bulk material processing, which are critical to advancing ultra-wide bandgap semiconductor technology.

it is reported that element six is ​​a subsidiary of diamond company de beers and is headquartered in london, uk. it is a leading company in the synthesis of single crystal diamond and polycrystalline diamond and has rich experience in chemical vapor deposition (cvd) technology.

element six’s contribution to the uwbgs program will leverage the company’s expertise in large-area cvd polycrystalline diamond and high-quality single crystal (sc) diamond synthesis to enable 4-inch device-grade sc diamond substrates.

sc diamond substrates are key to enabling advanced electronics, including high-power rf switches, radar and communications amplifiers, high-voltage power switches, high-temperature electronics for extreme environments, deep ultraviolet leds and lasers, supporting a multi-billion dollar systems market.

element six is ​​able to produce high-quality single-crystal diamond wafers with a highly ordered crystal structure. currently, sc diamond substrates are used in the monitoring system of the cern large hadron collider and helped discover the higgs boson particle. element six has collaborated with abb, a leader in high-power semiconductors, to realize the first high-voltage bulk diamond schottky diode. in addition, element six recently completed the construction and commissioning of an advanced cvd facility in portland, oregon, which utilizes its core technology and is powered by renewable energy.

in terms of polycrystalline diamond, element six's polycrystalline diamond wafers have a diameter of over 4 inches and are widely used in optical windows in euv lithography and thermal management applications in high-power density si and gan semiconductor devices.

in addition, in terms of high-voltage devices, element six has collaborated with swiss company abb to realize the first high-voltage bulk diamond schottky diode, demonstrating the potential of diamond-based semiconductors in changing the field of power electronics.

at the same time, element six is ​​expanding its core capabilities in diamond technology with its partners. through cross-licensing of intellectual property and equipment with japan's orbray. orbray has established manufacturing technology for single-crystal diamond substrates with a diameter of 55 mm (about 2 inches), which is larger than traditional substrates. this will combine element six's cvd (chemical vapor deposition) technology, which can deposit diamonds up to 150 mm (about 6 inches) in diameter, with orbray's expertise. the goal is to establish manufacturing technology for large-diameter single-crystal diamond substrates for next-generation power semiconductors and communication semiconductors with excellent pressure resistance and heat dissipation performance, expand the production scale of single-crystal diamond wafers, and occupy a larger market share in the ultra-wide bandgap semiconductor market.

separately, element six recently completed the construction and commissioning of an advanced cvd facility in portland, oregon, which is powered by renewable energy and capable of mass-producing high-quality single-crystal diamond substrates.

it should be emphasized that diamond is divided into single crystal and polycrystalline. polycrystalline diamond is generally used in heat sinks, infrared and microwave windows, wear-resistant coatings, etc., but it cannot really bring into play the excellent electrical properties of diamond. this is because there are grain boundaries inside it, which will cause the carrier mobility and charge collection efficiency to be greatly reduced, so that the performance of the electronic devices prepared by it is seriously inhibited; single crystal diamond does not have such concerns and is generally used in key areas such as detectors and power devices.

for many years, synthetic diamonds produced using high pressure and high temperature technology (hpht) have been widely used in abrasive applications, taking advantage of diamond's extremely high hardness and wear resistance. in the past 20 years, new diamond growth methods based on chemical vapor deposition (cvd) have been commercialized, allowing the production of single and multicrystalline diamonds at a lower cost. these new synthesis methods allow the full development of diamond's optical, thermal, electrochemical, chemical and electronic properties.

huawei's diamond layout

in november 2023, huawei and harbin institute of technology jointly applied for a patent entitled "a hybrid bonding method for three-dimensional integrated chips based on silicon and diamond". this patent involves a hybrid bonding method for three-dimensional integrated chips based on silicon and diamond.

specifically, the cu/sio2 hybrid bonding technology is used to integrate silicon-based and diamond substrate materials in three dimensions. huawei hopes to make full use of the different advantages of silicon-based semiconductors and diamonds through the combination of the two.

the patent document mentions, "with the continuous increase in integration density and the continuous reduction in feature size, the thermal management of electronic chips faces great challenges. the heat accumulated inside the chip is difficult to transfer to the heat sink on the surface of the package, resulting in a sudden rise in internal temperature, which seriously threatens the chip performance, stability and service life." this patent utilizes the high heat dissipation properties of diamond, and aims to provide a heat dissipation channel for three-dimensional integrated silicon-based devices to improve the reliability of the devices.

in march this year, professor yu daquan's team from xiamen university and the huawei team cooperated to develop a diamond low-temperature bonding technology based on reactive nanometal layers. they successfully integrated the polycrystalline diamond substrate onto the back of the 2.5d glass adapter package chip and used a thermal test chip (ttv) to study its heat dissipation characteristics.

Diamond Foundry，

growing the world's first single-crystal diamond wafer

diamond foundry, a company founded by engineers from mit, stanford university, and princeton university, has also made progress in diamond chips.

it is understood that the company hopes to use single-crystal diamond wafers to solve and limit the thermal challenges of artificial intelligence, cloud computing chips, electric vehicle power electronics devices and wireless communication chips.

in october 2023, diamond foundry produced the world's first single-crystal diamond wafer, which is 100 mm in diameter and weighs 100 carats. diamond foundry can now produce diamond wafers that are 4 inches long and wide and less than 3 mm thick in a reactor, and these wafers can be used together with silicon chips to quickly conduct and release the heat generated by the chips.

diamond foundry has developed a set of technologies to embed diamonds into each chip. diamonds are directly connected atomically to bond semiconductor chips to diamond wafer substrates to eliminate the thermal bottleneck that limits their performance.

heat situation comparison

(image source: diamond foundry)

the advantage of this approach is that it can make the chip run at least twice as fast as its rated speed. diamond foundry engineers said that using this method on one of nvidia's most powerful ai chips, under experimental conditions, it was even able to increase its rated speed by three times.

diamond foundry earlier revealed that it hopes to introduce single diamond wafers after 2023 and place a diamond behind each chip; it is expected to introduce diamond into semiconductors around 2033.

advent diamond: diamond doped with phosphorus

advent diamond in the united states is also a startup company dedicated to mass production of diamond semiconductor materials. in april this year, advent diamond disclosed its progress in this regard.

it is understood that one of advent diamond's core innovations is the ability to grow single-crystal phosphorus-doped diamond on a preferred substrate. it is the only company in the united states with this capability. phosphorus-doping technology is particularly significant because it can create n-type semiconductors in diamond, which is a key element in the development of electronic devices. in addition, advent diamond has also achieved milestone progress in growing boron-doped diamond layers over large areas, expanding the potential application areas of diamond-based electronics.

advent diamond's expertise is not limited to material growth, but also includes comprehensive component design, manufacturing and characterization capabilities. this includes advanced clean room processes such as etching, lithography and metallization, as well as a full set of characterization techniques such as microscopy, ellipsometers and electrical measurements. advent diamond said that it has used this cutting-edge growth technology to develop intrinsic diamond layers with extremely low impurity concentrations, ensuring the highest quality and performance standards for semiconductor-grade diamond materials.

it is understood that advent diamond currently has 1-2 inch diamond-embedded wafers and is working to expand the wafer size to 4 inches. however, defect density remains a key issue, with most wafers having defects of about 108/cm² or higher, and defects must be reduced to 103 defects/cm² to achieve the expected performance.

french company diamfab:

achieve 4-inch diamond wafers by 2025

in addition, diamfab, a semiconductor diamond startup based in france, is also working hard on diamond chip technology.

diamfab is a spin-off of the institut néel, a cnrs laboratory in france, and the result of 30 years of research and development in synthetic diamond growth. the diamfab project was initially incubated at satt linksium in grenoble alpes, and the company was founded in march 2019 by gauthier chicot and khaled driche, two phds in nanoelectronics and recognized researchers in the field of semiconductor diamond.

diamfab said that in order to meet the market needs of semiconductors and power components in the automotive, renewable energy and quantum industries, the company has developed breakthrough technologies in the field of epitaxy and doping of synthetic diamonds and has four patents. its expertise lies in the growth and doping of thin diamond layers and the design of diamond electronic components.

in march this year, the company announced a first round of financing of €8.7 million. this round of financing will enable diamfab to set up a pilot production line, pre-industrialize its technology, and accelerate its development to meet the growing demand for diamond semiconductors.

diamfab has applied for a patent for the all-diamond capacitor and is working with leading companies in the field. “among other parameters, we have achieved our goal: more than 1000a/cm²“we are excited to announce the launch of our new 4-inch silicon wafers, which will enable us to achieve high current density of 1000mw and breakdown electric field of greater than 7.7 mv/cm. these are key parameters for future device performance and are already superior to those offered by existing materials such as sic for power electronics. in addition, we have a clear roadmap to achieve 4-inch wafers by 2025 as a key enabler for mass production.”

japan is making full efforts in the diamond chip industry

judging from the research results that have been announced, japan's exploration of the industrialization of diamond chips is more comprehensive.

starting in 2022, japan produced diamond wafers of a purity that can be used for quantum computing projects; in early 2023, professors at saga university in japan and japanese precision parts manufacturer orbray collaborated to develop a power semiconductor made of diamond that can operate at 875 megawatts of electricity per 1cm², the highest output power value in the world among diamond semiconductors; in august of the same year, a research team at chiba university in japan proposed a new laser technology that can "effortlessly cut" diamonds along the optimal crystal plane.

chiba university research team cutting method

the laser-based cutting process can cleanly cut diamonds without damaging them. the researchers said the new technology prevents the propagation of undesirable cracks during laser cutting by focusing short laser pulses into a narrow, conical volume within the material.

chiba university said the newly proposed technology could be a key step in transforming diamonds into "semiconductor materials suitable for future more efficient technologies." professor hidai said cutting diamonds with lasers "enables the production of high-quality wafers at a low cost" and is essential for making diamond semiconductor devices.

akhan

akhan specializes in laboratory-made synthetic electronic-grade diamond materials. as early as august 2021, akhan announced that it had developed the first 300mm wafer combining cmos silicon with a diamond substrate, achieving a milestone.

around 2013, akhan obtained the exclusive diamond semiconductor application license for the breakthrough low-temperature diamond deposition technology developed by the u.s. department of energy's argonne national laboratory. this technology can deposit nanodiamonds on various wafer substrate materials at temperatures as low as 400 degrees celsius. the low-temperature diamond technology from argonne combined with akhan's miraj diamond process broke the barrier that the use of diamond films in the semiconductor industry was limited to p-type doping.

subsequently, akhan announced its miraj diamond platform, which has developed a patent-pending new process in which n-type diamond material is created on silicon with previously unproven properties.

in the previous article "diamond chips, commercial use is imminent" by semiconductor industry observer, it was mentioned that adam khan, founder and ceo of akhan, founded a new company diamond quanta in january this year, focusing on the semiconductor field, with the aim of using the excellent properties of diamond to provide advanced solutions for power electronics and quantum photonic devices.

in may, diamond quanta announced that it has a “unified diamond framework” that facilitates true substitutional doping. this innovative technology seamlessly incorporates new elements into the structure of diamond, giving it new properties without destroying its crystalline integrity.

diamond has thus been transformed into a high-performance semiconductor capable of supporting both negative (n-type) and positive (p-type) charge carriers. this level of mobility indicates that the diamond lattice is very clean and ordered, and that scattering centers have been effectively passivated due to the successful implementation of a co-doping strategy that mitigates the effects of carrier transport defects. in addition, the doping process refines the existing diamond structure by correcting dislocations, thereby improving the material's conductivity. these advances not only preserve but also enhance the diamond structure, avoiding common defects such as significant lattice distortion or the introduction of trap states that typically reduce mobility.

“starting diamond quanta and developing this advanced doping process was a necessity. industries such as electronics, automotive, aerospace, energy, and others have been searching for a semiconductor technology that can handle the growing pressures of their evolving demands for technology expansion,” said adam khan. “our technology is not just offering an alternative material to industries seeking to improve semiconductor efficiency; we are introducing an entirely new material that will redefine the standards for performance, durability, and efficiency, and it will play an integral role in seamlessly powering the increasingly heavy loads of the modern era.”

south korean team: reducing the cost of diamond film

in april this year, a materials science team from the institute for basic science in south korea published an article in nature magazine, announcing the successful synthesis of diamonds at standard atmospheric pressure and 1025°c. this preparation method is expected to open up a lower-cost path for the production of diamond films.

rodney ruoff, the head of the research team, said that a few years ago, he noticed that synthetic diamonds do not necessarily require extreme conditions. exposing liquid metal gallium to methane gas can produce diamond allotrope graphite, which inspired ruoff to study the route of "decarburization" of gallium-containing liquid gold from carbon-containing gas to produce diamond. by coincidence, ruoff's team discovered that when silicon was introduced into the reaction environment, tiny diamond crystals appeared. based on this phenomenon, the experimental team improved the reaction apparatus, exposing a mixture of liquid gallium, iron, nickel and silicon to a methane and hydrogen mixed atmosphere, and heating it to 1025°c, successfully generating diamonds without the use of high pressure and seed crystals. at present, ruoff's team has successfully prepared a micro-diamond film composed of thousands of diamond crystals.

if this normal-pressure synthesis technology can be successfully promoted to a larger scale in the future, it will open up a more economical and simpler path for the preparation of diamond films, and is expected to provide strong support for the development of quantum computers and power semiconductors.

not only the above-mentioned companies are promoting the industrialization of "diamond" chips, but also many other companies in the industry are also investing in it.

judging from various trends, the industry is paying more and more attention to diamond semiconductors, and advantageous resources are constantly gathering, which also accelerates the speed of research and development and industrialization. this means the beginning of the "diamond" wafer era.

in summary, diamond semiconductors have outstanding properties that are superior to other semiconductor materials, such as high thermal conductivity, wide bandgap, high carrier mobility, high insulation, optical transmittance, chemical stability and radiation resistance, etc. the industry is currently moving further towards diamond and gradually entering a transitional period of multifunctional development of diamond.

in the future, with the gradual development of large-size, high-quality, large-range, and highly flexible diamond deposition technology, the development of large-scale integrated circuits and high-speed integrated circuits is expected to enter a new era.

final thoughts

as early as 50 or 60 years ago, the scientific community had set off a wave of research on diamond semiconductors, but to this day, devices made of diamond semiconductors have not been used on a large scale. some engineers lamented that diamond may always be on the edge of practical semiconductors.

it is true that diamond has significant advantages in the semiconductor field, but the large-scale production and application of diamond chips still faces many challenges and limitations, such as high cost, difficult processing, immature technical processes such as doping, and limited application scope.

although this material still has a long way to go, it has shown vitality and application potential in the semiconductor chain. we believe that with the joint efforts of all parties, diamond materials with various excellent properties will be further developed in the future, helping the semiconductor material field take a crucial step forward.

of course, the ultimate role of new materials is not to beat traditional materials represented by silicon to death on the beach, but to serve as a complement and give full play to their areas of expertise.