Influence of SiON interlayer on the diamond/GaN heterostructures studied by Raman and SIMS measurements

Abstract

The effect of silicon oxynitride (SiON) layer on the thermally-induced stress of diamond-coated AlGaN/GaN heterostructures was studied by Raman and SIMS spectroscopy. Diamond films (0.8 or 2.8 µm in thickness) were grown by MWCVD on selected areas of AlGaN/GaN/Si substrates with SiON interlayer. The stress in diamond became tensile for the thinner strip in the range of 0 ÷ 0.5 GPa and compressive for the thicker strip in the range of −0.6 ÷ −0.1 GPa both measured at temperatures ranging from 50 to 400 °C. The applied SiON interlayer positively influenced the induced stress (Δstress decreased by about 0.14 GPa compared to the sample without SiON) independently on the thickness of the diamond film. SIMS depth profiling was applied to analyse the influence of diamond CVD on the AlGaN/GaN interface of SiON passivated samples. As observed, the hydrogen and carbon atoms were trapped in the SiON which acted as a stop layer.