TRANSISTOR WITH LONGITUDINAL STRAIN IN CHANNEL INDUCED BY BURIED STRESSOR RELAXED BY IMPLANTATION

摘要

Processes for making field effect transistors relax a buried stressor layer to induce strain in a silicon surface layer above the buried stressor layer. The buried stressor layer is relaxed and the surface layer is strained by implantation into at least the buried stressor layer, preferably on both sides of a portion of the surface layer that is to be stressed. For example, implanting ions through the surface silicon layer on either side of the gate structure of the preferred FET implementation into an underlying stressor layer can induce strain in a channel region of the FET. This process can begin with a silicon or silicon-on-insulator substrate with a buried silicon germanium layer having an appropriate thickness and germanium concentration. Other stressor materials can be used.

主权项

1. A method of manufacturing a semiconductor device, comprising:
providing a substrate comprising a wafer, a semiconductor surface layer, an insulation layer and a stressor layer positioned within the substrate so that the insulation layer is between the stressor layer and the semiconductor surface layer, wherein a stressed region of the stressor layer adjacent the insulation layer is in a stressed state in comparison to the wafer; forming a gate structure above the semiconductor surface layer; relaxing a first portion of the stressor layer under the gate structure so as to strain a first portion of the semiconductor surface layer under the gate structure, the relaxing accomplished by implanting into second and third portions of the stressor layer aligned with second and third portions of the semiconductor surface layer; and forming respective source and a drain regions in at least a part of the second and third portions of the semiconductor surface layer.