Method of forming diffusion region of semiconductor device by solid phase diffusion
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorShinji Funaba
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Abstract
An impurity is diffused into semiconductor epitaxial layers of a semiconductor device from a solid phase diffusion source through an additional thin film layer disposed on the epitaxial layers of the structure. After the diffusion, the thin film layer is removed. The material of the additional thin film layer has physical properties approximating those of the epitaxial layers. Accordingly, no crystallographic defects such as dislocations are introduced into the epitaxial layers by heat treatment, and, accordingly, the resulting device has reduced leakage current.
Claims17
A method of forming a diffusion region of a semiconductor device by solid phase diffusion comprising the steps of:
- epitaxially growing on a semiconductor substrate a plurality of semiconductor epitaxial layers sufficient for forming a semiconductor device;
- epitaxially growing at least one additional semiconductor layer on an uppermost one of the plurality of semiconductor epitaxial layers sufficient for forming a semiconductor device, said additional semiconductor layer not being essential for the operation of the semiconductor device and having a thermal expansion coefficient different from the thermal expansion coefficient of the uppermost semiconductor epitaxial layer by no more of the uppermost semiconductor epitaxial layer by no more than 3.times.10.sup.-6 /.degree.C.;
- placing a first solid phase diffusion source material on the additional semiconductor layer;
- heat treating the structure including the plurality of semiconductor epitaxial layers, the additional semiconductor layer, and the first solid phase diffusion source material to diffuse the first solid phase diffusion source material through the additional semiconductor layer and into the plurality of semiconductor epitaxial layers to a desired depth;
- and
- removing at least part of the additional semiconductor layer and the first solid phase diffusion material.
A method of forming a diffusion region of a semiconductor device by solid phase diffusion comprising the steps of:
- epitaxially growing on a semiconductor substrate a plurality of semiconductor epitaxial layers;
- epitaxially growing at least one additional semiconductor layer on an uppermost one of the plurality of semiconductor epitaxial layers, said additional semiconductor layer having a thermal expansion coefficient different from the thermal expansion coefficient of the uppermost semiconductor epitaxial layer by no more than 3.times.01.sup.-6 /.degree.C.;
- placing a first solid phase diffusion source material on the additional semiconductor layer;
- heat treating the structure including the plurality of semiconductor epitaxial layers, the additional semiconductor layer, and the first solid phase diffusion source material to diffuse the first solid phase diffusion source material through the additional semiconductor layer and into the plurality of semiconductor epitaxial layers to a desired depth;
- and
- removing the additional semiconductor layer and the first solid phase diffusion material.
Dependencies are inferred from the claim text.