Direct Photo Chemical Vapor Deposition of Silicon Nitride and Its Application to MIS Structre

Masahiro YOSHIMOTO  Kenji TAKUBO  Takashi SAITO  Tetsuya OHTSUKI  Michio KOMODA  Hiroyuki MATSUNAMI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E75-C   No.9   pp.1019-1024
Publication Date: 1992/09/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Silicon Devices and Materials)
Category: 
Keyword: 
direct photo-CVD,  silicon nitride,  MIS structure,  interface states,  rapid thermal anneal,  

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Summary: 
Silicon nitride (SiNx) films have been deposited at lower substrate temperatures (500) by direct (without mercury-sensitization) photo-chemical vapor deposition (photo-CVD) using SiH4 and NH3 with a low-pressure mercury lamp. Films deposited at around 350 have a polymeric structure such as (Si(NH)2)n. Films deposited at 500 were close to stoichiometric Si3N4 with a slight amount of hydrogen. The refractive index and the dielectric constant of films deposited at 500 became almost equal to the values of thermally synthesized Si3N4. The resistivity was as high as 51016 Ωcm. The minimum density of interface states in Al/SiNx/Si MIS (metal-insulator-semiconductor) diodes was estimated to be 91010 cm-2eV-1 by a quasi-static capacitance-voltage measurement. For SiNx films deposited at 300, the density of interface states, which was in the order of 1011 cm-2eV-1 as deposited, decreased by a rapid thermal anneal after the deposition. For Al/SiNx/InP MIS diodes, it was 31011 cm-2eV-1 by high-frequency capacitance-voltage measurements. Direct photo-CVD for SiNx films is promising for low-temperature formation of a gate insulator.