Passivation Study for In{sub}0.4AlAs/In{sub}0.65GaAs HEMTs By UHV RPECVD Grown SIN{sub}xx Dielectrics And Their Impact On I-V Kink Low-Frequency Dispersion Phenomena

摘要

The influence of Silicon Nitride (SiN{sub}x) passivation on the DC and low-frequency transconductance dispersion behaviours of In{sub}0.4AlAs/In{sub}0.65GaAs HEMTs has been investigated. Although the surface passivation using MBE grown thin InP etch-stop is effective to suppress I-V Kink phenomena, it has critical drawbacks of large gate leakage current, low gate turn-on (V{sub}(on)) and breakdown voltage (BV{sub}(gd)) due to low schottky barrier height (SBH) of InP layer. To resolve this problem, we have developed innovative SiN{sub}x passivation process to prevent I-V kink as well as to maintain low gate leakage current by UHV Remote-PECVD system. Through the optimized SiN{sub}x passivation process, the DC I-V Kink and the low-frequency transconductance dispersion could be significantly improved.