In:
MRS Proceedings, Springer Science and Business Media LLC, Vol. 284 ( 1992)
Abstract:
Nitrogen-rich amorphous silicon-nitride films a-Si 1−x N x :H were prepared by glow-discharge decomposition of gas mixtures of ammonia and silane. With increasing nitrogen content the spin density, N s , decreases from 4×10 18 cm −3 (x = 0.55) to 3×10 17 cm −3 (x = 0.67). These films were used as a gate dielectric in amorphous silicon TFTs. The TFTs are characterized by measurements of the transfer characteristics and by a transient current spectroscopy (TCS). Nitrogen-rich dielectrics with N s 〈 10 18 cm −3 have little influence on the transfer characteristic, however, they tend to have a lower sensitivity to bias stress. Using a device-quality nitride (x = 0.64) the properties of the TFTs were varied in two ways: 1) doping of the a-Si:H film with phosphine or diborane and 2) exposure of the nitride film to an oxygen plasma. The variation of the areal density of defect states, N d , with E c -E F suggests that the effective density of interface states, N i , and the characteristic of undoped TFTs are determined by interface defects of the a-Si:H film. The plasma treatment introduces oxygen into a thin superficial layer of the nitride. By varying the exposure time t e it is possible to change the properties of the TFTs continuously from nitride like to oxide like.
Type of Medium:
Online Resource
ISSN:
0272-9172
,
1946-4274
DOI:
10.1557/PROC-284-395
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
1992
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