Method for Reducing doping Distribution Variation in Semiconductor Wafers
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
This article describes a method for reducing the doping distribution variation across a semiconductor wafer surface by preventing oxide formation on the wafer surface prior to the doping of the surface. This is accomplished by preventing oxygen from entering the system except during the time that the doping gas is injected into the system. For example, in the case of phosphorus doping of a semiconductor wafer, if the oxygen is excluded except when the PoCL3 is injected into the tube, it has been found that the same impurity concentration on the surface and doping profile can be obtained with using 40% less dopant. Moreover, the dopant in the wafer is significantly improved. Also, excluding the oxygen prior to the introduction of the dopant reduces the process time by approximately 18%.