Method of making a semiconductor device

A method of making a semiconductor device comprising:

• a. preparing a semiconductor substrate;
• b. depositing a non-monocrystalline semiconductor layer doped with predetermined impurity atoms on at least a portion of said semiconductor substrate;
• c. depositing an oxide layer doped with the same type impurity atoms as said predetermined impurity atoms on said non-monocrystalline semiconductor layer, thus forming a double layer diffusion source;
• d. heating the semiconductor substrate to diffuse said impurity atoms from said double layer diffusion source into the semiconductor substrate and to form a diffused region in the substrate;
• e. removing said double layer diffusion source to expose a fresh surface of the semiconductor substrate;
• f. forming an epitaxial semiconductor layer on the fresh surface of the semiconductor substrate;
• and
• g. forming semiconductor device elements in said epitaxial semiconductor layer.

A method of making a MOS field effect transistor comprising:

• a. forming a diffusion mask layer on the surface of a semiconductor substrate;
• b. forming windows in said diffusion mask layer through which source and drain diffusion is carried out;
• c. depositing a non-monocrystalline semiconductor layer doped with predetermined impurity atoms on the diffusion mask layer and within the windows;
• d. depositing an oxide layer doped with the same type impurity atoms as said predetermined impurity atoms on said non-monocrystalline semiconductor layer, thus forming a double layer diffusion source;
• and
• e. heating the semiconductor substrate to diffuse said impurity atoms from said double layer diffusion source into the semiconductor substrate and to form source and drain regions in the substrate.