Method of forming shallow diffusion layers in a semiconductor substrate in the vicinity of a gate electrode

摘要

A method of forming shallow diffusion layers in a semiconductor substrate is provided wherein the shallow diffusion layers are positioned in the vicinity of edge portions of a gate electrode and laterally extend from source/drain diffusion layers having a bottom level deeper than the shallow diffusion layers. The above method comprises the following steps. Crystal defects are selectively formed at least in predetermined shallow regions positioned in a surface region of the semiconductor substrate and in the vicinity of the edge portions of the gate electrode. The predetermined shallow regions are laterally in contact with impurity-introduced deep regions having been formed. The predetermined shallow regions have a bottom level shallower than the impurity-introduced deep regions. Subsequently, the semiconductor substrate is subjected to a heat treatment not only to cause a vertical diffusion of an impurity from the impurity-introduced regions so as to selectively form the source/drain diffusion layers but also to cause a rate-increased lateral diffusion of the impurity from the impurity-introduced regions through the predetermined shallow regions so as to selectively form the shallow diffusion layers.