InP MISFET´s with Al2O3/Native Oxide double-layer gate insulators

Enhancement-mode InP MISFET´s with anodic Al2O3/ native oxide double-layer for gate insulator are fabricated by anodization processes in electrolyte and in oxygen plasma. Such gate structure greatly improves the device performance; high effective electron mobilities of 1500-3000 cm²/V . s and marked reduction of drain current instability were simultaneously achieved. This device performance is consistent with the interface properties obtained by C-V measurements. InP MISFET inverters as well as ring oscillators are also fabricated to demonstrate the stability of the circuit at low frequency and to show the capability of the process employed.