Power-hungry applications, such as high-performance artificial intelligence (AI) chips, graphical processor unit (GPU) chips, and harsh environment applications, have pushed the semiconductor industry to look beyond silicon carbide (SiC) and gallium nitride (GaN) devices because the transistor size decreases to improve computing speed, and the power consumption increases dramatically as well when processing huge amounts of data. In the case of harsh environment applications, such as spacecraft, devices must function effectively at high temperatures, which will be effective when diamond semiconductors are used. Moreover, reports have emerged that indicate diamond-based sensors are being developed to aid the life sciences industry.
Therefore, the demand for diamond devices has increased, especially for high-power devices because of their electrical resistivity and heat dissipation capabilities. In addition, several compound semiconductor materials, such as SiC and GaN, have been explored in the past; however, the breakdown voltage of these materials still poses a limitation for high-power applications. Therefore, a new class of material (diamond) has been explored because of its superior intrinsic characteristics, such as higher breakdown voltage, electron mobility, and superior thermal conductivity. Furthermore, diamond’s breakdown strength is estimated to be at least five times higher than SiC and 15 times higher than silicon wafers.
Applications that need to operate in extreme conditions include automotive engines, spacecraft, data centers, and defense technologies. High-power radio frequency (RF) electronics are needed in evolving communication technologies as well. Moreover, because diamond-based power devices perform more efficiently and reliably, building greener electronic systems are possible.
Diamond semiconductors’ potential is available for power devices partly because of the development of design and processing technologies. For instance, the fin field-effect transistor (FinFET) processing technology can improve the diamond semiconductor’s conductivity without the need to add dopants in the channel. On the other hand, researchers are working on the metal-oxide-semiconductor field-effect transistor (MOSFET) by using the deep-depletion of a bulk boron-doped diamond. The research on MOSFET-based devices will enable the production of the simple device structure and improve the magnitude of mobility of charge carriers.
Eventually, the resultant diamond-based device will demonstrate higher-power performance and durability, even under extreme temperatures and other external factors. With advancements in processing technologies, such as epitaxy, selective doping, and lithography, the formation of a diamond-oxide interface for devices such as transistors and diodes will be easier. Because of such developments, diamond semiconductors can achieve high-speed switching as well.
Given all the positive factors, the term diamond semiconductor might sound costly to integrate with electronics; however, the industry is not mining diamonds but artificially growing electronics-grade diamonds. Synthetic diamonds are manufactured by processing methane gas in a microwave plasma chemical vapor deposition (MPCVD) reactor. This process produces a perfect diamond substrate on which active and passive semiconductor devices can be fabricated.
The diamond semiconductor market is in the emerging stage; therefore, the market is witnessing a growth challenge in terms of high investment costs. This cost pressure is in terms of synthetic diamond production as well as the process equipment that supports production. Specifically, the doping of devices to fabricate n-type semiconductors has technical challenges; therefore, several research activities are focused on improving the doping techniques. Researchers believe that breaking the barrier in doping will help realize the full potential of diamond semiconductors. Because using diamond semiconductors is still in the research and development (R&D) phase, demand is expected to be low in the short term; therefore, an investment surge on fabrication facilities is not expected. As a result, prices will remain high and create an entry barrier for emerging market participants.
In conclusion, diamond-based power semiconductors will enable several mission-critical applications; however, in the current scenario, the market is in the R&D phase, and market participants are working on cost-effective processing technologies to improve performance as well. Eventually, the potential of diamond-based power semiconductors to replace all other existing technologies will be highly dependent on the cost-to-performance ratio rather than on existing technologies. Therefore, the ability of diamond semiconductors to grow into mainstream power semiconductors may not be possible, at least in the near future.
