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

Summary :

Silicon nitride (SiN_x) 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/SiN_x/Si MIS (metal-insulator-semiconductor) diodes was estimated to be 910¹⁰ cm^-2eV^-1 by a quasi-static capacitance-voltage measurement. For SiN_x 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/SiN_x/InP MIS diodes, it was 310¹¹ cm^-2eV^-1 by high-frequency capacitance-voltage measurements. Direct photo-CVD for SiN_x films is promising for low-temperature formation of a gate insulator.

• Publication: IEICE TRANSACTIONS on Electronics Vol.E75-C No.9 pp.1019-1024
• Publication Date: 1992/09/25
• Type of Manuscript: Special Section PAPER (Special Issue on Silicon Devices and Materials)

Authors

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

Keyword

direct photo-CVD,  silicon nitride,  MIS structure,  interface states,  rapid thermal anneal