US Patent 10529739 Asymmetric band gap junctions in narrow band gap MOSFET

A semiconductor device with one or more fin structures formed from a first material, gate, source, and drain regions formed from a second material, and a contact insulator layer deposited over the substrate, where an etching process applied to the substrate removes the insulator to create a trench over the source region. The device also includes a lower band gap source material that is deposited into the trench, a second contact insulator layer, and a metalizing material that is deposited over the substrate. In some embodiments, the device also includes a higher band gap source material that is deposited into the trench, a second contact insulator layer, and a metalizing material that is deposited over the substrate.