Charged Defect Quantification in Pt/Al2O3/In0.53Ga0.47As/InP MOS Capacitors

Abstract

This work focuses on the separation and quantification of fixed bulk oxide charge, fixed charge at the dielectric–semiconductor interface and interface state charge components in the Pt/Al2O3/In0.53Ga0.47As metal-oxide-semiconductor (MOS) system. The availability of atomic layer deposited Al2O3 dielectrics over n- and p-type In0.53Ga0.47As with a range of well-controlled thickness values opens up an experimental route for the determination of the interface state density (Dit) independently of the total fixed oxide charge using capacitance–voltage measurements taken at 1 MHz and −50°C. Low temperature forming gas annealing (350°C) significantly reduces the amount of fixed charge. The interface fixed charge is reduced from ∼ −8.5 × 1012 cm−2 preanneal to ∼ −7.4 × 1011 cm−2 postanneal and the bulk oxide charge is reduced from ∼1.4 × 1019 cm−3 preanneal to ∼5 × 1018 cm−3 postanneal. The forming gas anneal also has a significant effect on the interface state charge, reducing its density from 1.3 × 1013cm−2 preanneal to 4 × 1012 cm−2 postanneal.