Project R-9115

Low temperature CVD diamond growth on GaN and GaN devices (Research)

GaN is the material of choice for high-power, high-frequency, and high-T electronics, but it has very low thermal conductivity, which overheats the electronic devices and diminishes device life. Diamond has the highest thermal conductivity among all the known materials. So, it would be ideal if GaN devices could be integrated with diamond as a heat sink material. But integration of diamond with GaN has been a challenge, since they have dissimilar crystal structures. Attempts have been made to put intermediate buffer layer to release strain between diamond and GaN crystals. But not many research has been carried out in trying different combinations of AlGaN/GaN heterostructures for depositing diamond by CVD. The main reason is the high processing temperature of diamond under conventional microwave plasma CVD conditions, which inevitably etches the GaN surface. It has been found that temperature above 600°C is detrimental for GaN material, So an innovative linear antenna microwave plasma enhanced (LA MW PE) CVD process will be adopted in the present research work, which has so far not been tried for depositing diamond on GaN substrate. LA MW PE CVD can grow high quality diamond crystals even at 300°C. Moreover, tuning of reactor parameters can lead to bigger grain sizes and flat plat morphology, ideal for heat spreading. After integration of two dissimilar wide band gap materials their electrical/thermal properties will be investigated for micro- and nano-electronics.

01 October 2018 - 30 September 2021