Method for smoothing polysilicon gate structures in CMOS devices
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChu-Yun Fu, Chung-Long Chang, Syun-Ming Jang, Shwangming Jeng
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Abstract
There is provided a method for smoothing the surface of undoped polysilicon regions of a CMOS structure, primarily gate regions. A direct HPD-CVD argon sputter is used improve the surface roughness by a factor of more than 50%. The argon plasma sputter may be used either alone or in conjunction with a thin capping layer of oxide, nitride or oxynitride. The devices manufactured using the process exhibit excellent electrical characteristics and improved reliability compared to devices made using conventional manufacturing processes.
Claims5
A method for manufacturing CMOS semiconductor devices having smooth polysilicon gate structures, the steps comprising:
- a) providing a silicon substrate having a gate oxide layer deposited thereupon;
- b) depositing a polysilicon layer having a predetermined thickness and a surface roughness of a first value on said gate oxide layer;
- and
- c) performing a direct argon sputter of said polysilicon layer in a high density plasma chemical vapor deposition chamber at an energy level of approximately 1300 watts top source rf plus approximately 3100 watts top and side source rf energy and approximately 800, watts rf bias, whereby said surface roughness is reduced to a second value.
Dependencies are inferred from the claim text.