Phosphorus Direct Doping from Vapor Phase into Silicon for Shallow Junctions

Abstract

Characteristics of shallow n‐type layers formed by direct doping of phosphorus from the vapor phase are presented. Shallow doped layers can be formed with depths less than 100 nm using as a source gas and hydrogen as a carrier gas. It is found that the phosphorus concentration on the surface is constant with the doping time and is determined by the flow rate of , not by the solid solubility. By varying the flow rate of , the surface phosphorus concentration is controlled in the range of 1018 to 1019 cm−3. These results show that impurities with low sticking coefficients to silicon and high vapor pressure, such as phosphorus, can be incorporated using this process, although the doping efficiency of phosphorus is low.