Rapid thermal annealing and the anomalous threshold voltage shift of metal-oxide-semiconductor structure in n+ polycrystalline silicon gate complementary metal-oxide-semiconductor technology

Abstract

An anomalous different threshold voltage shift between P-channel metal-oxide-semiconductor field effect transistor (P-MOSFET) and N-channel MOSFET under high temperature rapid thermal annealing (RTA) borophosphosilicate glass reflow has been studied using 1 μm n+ polygate complementary MOS technology. The boron transient enhanced outdiffusion and phosphorus pileup at channel surface, as well as the interface states generated due to the degradation of thin gate oxide under high RTA process, are proposed as the main sources of this anomalous shift. A detailed model is proposed to interpret the mechanism and some methods to solve the anomalous shift are suggested.

Electrically Active Interface Defects in Si(100)/SiO2 and Si(100)/HfO2 Structures

“…For the Si/SiO 2 system, a review will be presented on the energy distribution of interface states following rapid thermal annealing (RTA) in an N 2 ambient for the thermally oxidized Si(100), Si(110) and Si(111) orientations. Following RTA, atypical features are commonly observed in the CV characteristics of polysilicon/SiO 2 /Si(100) structures [3,4], and an examination of the interface states from CV analysis combined with electron spin resonance (ESR), identifies the effect as due to H dissociation from P bo /(P b1 ) dangling bond centres due to the RTA step. The energy distribution of interface states for the H free Si(100)/SiO 2 system, is used as a baseline for comparisons to Si(100)/HfO 2 structures.…”