GaN-on-diamond: The next GaN

Engineers in the defense community have long sought to replace the bulky and heavy traveling wave tubes (TWT) used in high power systems such as radar, communications satellite and electronic warfare (EW) with compact, lightweight, cheaper and more efficient semiconductor components. Diamond is also an excellent electrical insulator - a property needed for high frequency power amplifiers. Additionally, the spatially shrunken GaN-on-diamond devices can operate amidst a much higher ambient temperature compared to GaN-on-SiC. This is due to the reduced thermal impedance stack between the GaN channel and the substrate/package. Key to the success of GaN-on diamond is that the diamond can be grown to within tens of nanometers of the GaN epitaxy maximizing its heat spreading function. In understanding whether the GaN-on-diamond wafer formation process used here negatively affected the GaN epitaxy, numerous tests were conducted on the GaN epitaxy including high-resolution X-ray, CV, Lehighton, Low-Temp PL, Hall and TEM.