Method for heteroepitaxial growth using tensioning layer on rear substrate surface

A method for forming a substantially planar epitaxial layer of a first semiconductor material on a second semiconductor material, said second material having first and second opposing surfaces, the method reducing warpage effects caused by said first material having a different coefficient of thermal expansion than said second material, the method comprising the steps of:

• forming a layer of tensioning material on the second surface, said tensioning material having a different coefficient of thermal expansion than said first material;
• forming a layer of said first semiconducting material on the first surface;
• and
• exerting counteracting stresses on the first and second surfaces by cooling said first material and said tensioning material so that the resulting shape of said second material is substantially planar.

An improved method of forming a gallium arsenide layer on a first surface of a silicon substrate, said silicon substrate having a second surface opposite said first surface, said method comprising:

• forming a layer of a first metal silicide on said second surface of said silicon substrate;
• forming a layer of gallium arsenide on said first surface of said silicon substrate;
• heating said layer of said metal silicide to approximately its annealing temperature;
• and
• cooling said layer of said metal silicide from approximately its annealing temperature so that said layer of said metal silicide exerts a tensioning force across said second surface of said silicon substrate which counters warping effects of a tensioning force exerted on said first surface on said silicon substrate by said layer of gallium arsenide so that said first surface of said silicon substrate has a substantially planar orientation.