LPCVD of Polysilicon by Hydrogen Reduction of Dichlorosilane
Original Publication Date: 1984-Feb-01
Included in the Prior Art Database: 2005-Feb-02
The standard process for polysilicon by low pressure chemical vapor deposition (LPCVD) uses 100% silane flowing at approximately 100 standard cubic centimeters per minute into a chamber at 625ŒC with an inlet pressure of from 0.100 torr to 0.500 torr. To get uniform-thickness coatings on single wafers that are stacked closely to one another, pressures on the order of one one-thousandth of atmospheric pressure is necessary. A uniform-thickness polysilicon film may be deposited with a reasonable growth rate and at only one twentieth of atmospheric pressure while using close wafer spacing in the deposition reactor. However, instead of using silane, dichlorosilane is used as the silicon source gas. In addition, hydrogen is used to reduce the dichlorosilane to silicon and hydrogen chloride gas.