Phosphorous passivation of the SiO2/4H-SiC interface

We describe experimental and theoretical studies to determine the effects of phosphorous as a passivating agent for the SiO2/4H-SiC interface. Annealing in a P2O5 ambient converts the SiO2 layer to PSG (phosphosilicate glass) which is known to be a polar material. Higher mobility (approximately twic...

Full description

Saved in:
Bibliographic Details
Published in:Solid-state electronics 2012-02, Vol.68, p.103-107
Main Authors: SHARMA, Y. K, AHYI, A. C, ISSACS-SMITH, T, SHEN, X, PANTELIDES, S. T, ZHU, X, FELDMAN, L. C, ROZEN, J, WILLIAMS, J. R
Format: Article
Language:English
Subjects:
Annealing
Applied sciences
Carbon
Density
Dielectric, amorphous and glass solid devices
Electronics
Exact sciences and technology
Passivation
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
Silicon carbide
Silicon dioxide
Threshold voltage
Transistors
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We describe experimental and theoretical studies to determine the effects of phosphorous as a passivating agent for the SiO2/4H-SiC interface. Annealing in a P2O5 ambient converts the SiO2 layer to PSG (phosphosilicate glass) which is known to be a polar material. Higher mobility (approximately twice the value of 30-40 cm2/V s obtained using nitrogen introduced with an anneal in nitric oxide) and lower threshold voltage are compatible with a lower interface defect density. Trap density, current-voltage and bias-temperature stress (BTS) measurements for MOS capacitors are also discussed. The BTS measurements point to the possibility of an unstable MOSFET threshold voltage caused by PSG polarization charge at the O-S interface. Theoretical considerations suggest that threefold carbon atoms at the interface can be passivated by phosphorous which leads to a lower interface trap density and a higher effective mobility for electrons in the channel. The roles of phosphorous in the passivation of correlated carbon dangling bonds, for SiC counter-doping, for interface band-tail state suppression, for Na-like impurity band formation and for substrate trap passivation are also discussed briefly.
ISSN:0038-1101
1879-2405
DOI:10.1016/j.sse.2011.10.030