Influence de la technique de dépôt d'isolant et des modes de décapage du semiconducteur sur les propriétés électriques de structures métal-Al 2O3-InP

Abstract

The purpose of this study is to establish the effect of the indium phosphide surface native oxide on the electrical properties of the InP-Al 2 O 3 interface for insulated gate field effect transistor. Metal-Al 2 O 3 -InP structures were fabricated using three different techniques for alumina deposition on n type (1,0,0) InP substrates: reactive ion sputtering, electron gun evaporation and reactive thermal evaporation. Two preliminary etching procedures were tested: one based on a HF solution which is known to remove InP native oxide and the other based on a NH 4 OH solution which favours the formation of a stable native oxide layer. No intrinsic effects were detected with the two evaporation techniques which do not degrade the InP-Al 2 O 3 interface. This was not the case using reactive ion sputtering. In return the formation of stable native oxide layer leads to a notable decrease of the interface state density (N ss =4×10 11 eV −1 cm −2 near the conduction band edge). By comparison to HF, the NH 4 OH etching procedure should result in an increase of the effective mobility of InP MISFET channel electrons Identification de l'influence de l'oxyde natif de InP sur les proprietes electriques de l'interface InP-Al 2 O 3 en vue de la realisation de transistors a effet de champ a grille isolee. Des structures Metal-Al 2 O 3 -InP ont ete realisees par trois techniques de depot de la couche d'alumine sur InP (1,0,0) de type n