This Small Business Innovation Research (SBIR) Phase II project will develop a unique solid-state microwave technique capable of reaching ultra-high temperature (up to 2150 deg C) and ultra-fast thermal processing of large wide band gap semiconductor wafers. It is widely recognized that the existing post-implant anneal process is a bottleneck limiting the performance and reliability of wide band gap semiconductor devices. This technique lowers the sheet resistance and surface roughness of the implanted semiconductor, enabling the fabrication of higher performance, more power efficient devices at lower cost. As part of the Phase I research, the microwave annealed samples showed a record low sheet resistance and surface roughness in both p-type and n-type implanted SiC. The Phase II research is to extend microwave-based rapid thermal processing (RTP) to other wide band gap materials such as GaN and to allow for RTP of larger sized wafers. The prototype system will be upgraded from a single-heating-head system to a system with an array of multiple heads and multiple sensors. Computer-based automated control will be developed to regulate wafer temperatures uniformity and stability. The research is anticipated to show feasibility of microwave-based RTP in commercial use for large SiC wafers. The technology improves post-implant anneal process to minimize sheet resistance and surface roughness of SiC and GaN, which consequently reduces the device power consumption and lowers the thermal budget. Lower surface roughness improves SiC sub-micron device reliability, consequently improving yield and reducing manufacturing cost.
Commercially, this is an enabler technology that will make better and lower-cost compound semiconductor devices in areas such as power devices, light emitting diodes (LEDs), high temperature and high frequency electronics. The societal and commercial impact of the technology can be enormous. LED technology, for example, can potentially reduce the percentage of energy required for lighting in the U.S. from 22% to 7%, saving $17 billion per year and reduce CO2 emissions by 155 million tons. Manufacturers of LED devices are looking for enabler technologies such as RTP to reach this goal. Recognizing the technological and the commercial significance of the research, Cree, GE Research and ARL are supporting the research effort by providing the technological expertise, test wafers, access to equipment, and other in-kind services. Furthermore, the technology can be extended to other applications such as RTP of ultra-shallow junction for nano-scale CMOS devices, wafer bonding, MEMS as well as processing of SiC nano-materials.
