Study on thermal stability of plasma-PH3 passivated HfAlO/In0.53Ga0.47 as gate stack for advanced metal-oxide-semiconductor field effect transistor

Abstract

In this work, we studied the thermal stability of a plasma- PH3 passivated HfAlO/ InGa0.53As0.47 gate stack for high speed metal-oxide-semiconductor field effect transistor (MOSFET) application, and results show excellent thermal stability up to 800°C with negligible changes in the equivalent oxide thickness, interface trap densities (Dit), and subthreshold slope. An increase in leakage current (1.10 × 10-4 A/ cm2 at Vg =1.5 V) after 800°C anneal can be attributed to the localized thinning of the gate dielectric and the rough interface caused by the out-diffusion of Ga/As, as observed by transmission electron microscopy and energy dispersion X-ray analysis. Dit measurement by the charge-trapping method showed suppressed Dit at the upper half of the bandgap for plasma-PH3 passivated devices, which is favorable for n-channel MOSFET operation. © 2010 The Electrochemical Society.