Influence of a thick nitride layer on transmission loss in GaN-on-3C-SiC/low resistivity Si

Wereporttheeffectofathicknitridelayerontransmissionlossin GaN-on-3C-SiC/low resistivity Si (LR-Si). Microstrip lines of finite length and width with ground pads were fabricated on three GaN-on-3C-SiC/LR-Si epitaxial structures with varying nitride layer thicknesses of 3.2, 5.3, and 8.0 𝜇 m. The loss performance of microstrip lines on different substrates was evaluated in the frequency range of 0.1 to 9 GHz. The sample with 8.0 𝜇 m thick nitride layer showed a minimal loss of 0.3 dB/mm at 9 GHz compared to the other samples. The evaluated data from electromagnetic (EM) simulation also confirmed a decreasing trend of loss with increasing nitride layer thickness. Temperature dependent loss evaluation also verified the above fact.