Tungsten chemical vapor deposition characteristics using SiH4in a single wafer system
作者:
Richard S. Rosler,
John Mendonca,
M. John Rice,
期刊:
Journal of Vacuum Science&Technology B: Microelectronics Processing and Phenomena
(AIP Available online 1988)
卷期:
Volume 6,
issue 6
页码: 1721-1727
ISSN:0734-211X
年代: 1988
DOI:10.1116/1.584167
出版商: American Vacuum Society
关键词: CHEMICAL VAPOR DEPOSITION;VAPOR DEPOSITED COATINGS;TUNGSTEN;SILICON;ADHESION;THIN FILMS;ELECTRIC CONDUCTIVITY;VERY HIGH TEMPERATURE;THICKNESS;IMPURITIES;W
数据来源: AIP
摘要:
Several workers have recently begun using silane as a high‐rate, low‐temperature alternative to hydrogen for the reduction of WF6in the chemical vapor deposition of W. The deposition and film characteristics of both selective and blanket W using this new chemistry are explored in a radiantly heated single wafer system using closed‐loop temperature control with a thermocouple in direct contact with the backside of the wafer. Selective W deposition rates of up to 1.5 μm/min were measured over the temperature range 250–550 °C with blanket W rates typically 2–5× lower. Resistivity is in the 10–15 μΩ cm range at 300 °C for SiH4/WF6ratios of 0.2 to 1.0, while above 400 °C the range is 7.5–8.5 μΩ cm. Si content in the W films is quite low at 1016to 1017atoms/cm3. Adhesion to silicon is excellent at temperatures of 350 °C and above. Selective W using SiH4reduction for doped silicon contact fill shows none of the consumption or encroachment problems common to H2reduction, although selectivity is more sensitive. Contact resistance forp+andn+silicon contacts are comparable to aluminum controls and to previously published data. Blanket deposition into narrow geometries gives ≥90% step coverage and without keyholes in the 250–450 °C deposition temperature range. For low‐SiH4flows, deposition at 500 °C causes small keyholes, while at 550 °C even larger keyholes result. At higher SiH4flows, keyholes are typically not seen from 250 to 550 °C. The SiH4‐reduced films are much smoother as indicated by reflectivities that are 2–4×higher than for the H2‐reduced films.
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