Asymmetric junction engineering for narrow band gap MOSFET
A method for forming a semiconductor device. It includes forming fin structures on a substrate, where the fin structure defines source and drain regions. It also includes forming a gate stack in contact with the fin structure, depositing an insulator on the substrate, and applying an etching process to remove portions of the insulator to form a trench to the source region. It also includes implanting a damaged epitaxial material into the trench and to the source regions, and applying a second etching process to remove portions of the insulator to form a trench in the insulator to the drain regions. Finally, the method includes growing an epitaxial junction material over the source and drain regions, and depositing a metal over the substrate.
1. A method for forming a semiconductor device, the method comprising:
forming one or more fin structures on a semiconductor substrate, wherein the fin structure defines a source and drain region;
forming a gate stack in contact with the fin structure;
depositing a contact insulator layer on the substrate;
applying a first etching process to remove exposed portions of the contact insulator layer, adjacent to the fin structure, to form a trench in the contact insulator layer that extends to the source region;
implanting a damaged epitaxial material into the trench formed by the first etching process and extending to the source region;
applying a second etching process to remove exposed portions of the contact insulator layer, adjacent to the fin structure, to form a trench in the contact insulator layer that extends to the drain region;
growing an epitaxial junction material over the source and drain regions after the first and second etching processes;
depositing a metalizing contact material over the substrate; and
planarizing the substrate after depositing the contact insulator layer.
2. The method of claim 1 , wherein the fin structure is comprised of indium gallium arsenide (InGaAs) or silicon germanium (SiGe).
3. The method of claim 1 , wherein the damaged epitaxial material is comprised of silicon (Si), argon (Ar), xenon (Xe), or germanium (Ge).
4. The method of claim 1 , wherein the fin structure is instead a nanowire, a nanosheet, or a planar device.
5. The method of claim 1 , wherein the fin structure is formed by Aspect Ratio Trapping (ART) or Strain Relaxed Buffer (SRB) processes.
6. The method of claim 1 , wherein the epitaxial junction material is grown, doped, and diffused with n+material for NFET devices and p+material for PFET devices.
7. The method of claim 1 , wherein the epitaxial junction material possesses higher leakage rates due to defects, physical damage, or doping introduced into the material, and is characterized by having a growth temperature too low to anneal all damage.
8. The method of claim 1 , wherein the trench instead extends to the drain region and damaged epitaxial material is injected into the trench and extends to the drain region.