The effect of different silicon nitride passivation recipes on the DC characteristics of AlGaN/GaN HEMTs

The changes in dc characteristics of AlGaN/GaN HEMT after ICP-CVD silicon nitride (SiN
_x
) passivation using two different recipes were investigated. Room temperature Raman analysis was performed to determine the stress state of the AlGaN layer after SiN
_x
passivation. The changes in the stress state of the device after passivation was correlated with the shift in threshold voltage and changes in drain current. DC measurement was used as a quick method to assess the drain current collapse. The degree of current collapse in the samples passivated with two different recipes is discussed in the light of the results, and hypothesis and explanations reported in the literature.