Device degradation during low temperature ECR-CVD. PART III: GaAs/InGaP HEMTs

Abstract

GaAs/InGaP HEMTs were coated with ∼200 Å of SiN X using electron cyclotron resonance chemical vapor deposition with the SiH 4/N 2 plasma chemistry. There is less degradation in transconductance, reverse breakdown voltage, threshold voltage and gate contact ideality factor for deposition pressures above ∼20 mTorr and for ECR source powers above 300 W. Both of these results appear to be due to the higher deposition rate under these conditions, which more rapidly covers the semiconductor surface, preventing ion damage and incorporation of atomic hydrogen.