Silane and Ammonia Surface Passivation Technology for High-Mobility In0.53Ga0.47As MOSFETs

We report the integration of silane and ammonia (SiH4 + NH3) surface passivation technology to realize high-quality gate stack on a high-mobility In0.53Ga0.47 As compound semiconductor. Vacuum anneal at 520 degrees C desorbs the native oxide while preserving the surface morphology and material composition of In0.53Ga0.47 As. By incorporating SiH4 + NH3 passivation, a thin silicon oxynitride (SiOxNy) interfacial layer was formed during high-k dielectric deposition. In0.53Ga0.47 As n-MOSFETs with SiH4 + NH3 passivation demonstrate significantly reduced subthreshold swing and OFF-state leakage current I-off in comparison with control In0.53Ga0.47 As n-MOSFETs without passivation. This is due to significant reduction of interface state density D-it. Improvement in carrier mobility over the control In0.53Ga0.47 As n-MOSFETs was also achieved with SiH4 + NH3 passivation.