Buried field shield in III-V compound semiconductor trench MOSFETs via etch and regrowth
| DWPI Title: III-V compound semiconductor trench MOSFET, has buried field shield electrically connected to body layer, drain contact to substrate, gate contact that partially fills gate trench on gate dielectric layer, and source contact contacting source layer |
| Abstract: The present invention is directed to III-V semiconductor trench MOSFETs comprising a buried field shield. The invention is further directed to an etch and regrowth method for forming this buried field shield. For example, in III-V trench MOSFETs with an n-type substrate, the region can be formed by an etch into the drift (n-type) and regrowth of p-type semiconductor to form the buried field shield in the trench area and a body/channel outside the trench area. With a narrow trench feature size, the regrowth will planarize enabling subsequent source epitaxy (n-type) without requiring ex-situ processing between body/channel and source growths, eliminating the need for additional masking of the regrowth. |
| Use: III-V compound semiconductor trench metal-oxide-semiconductor field-effect transistor (MOSFET) for use as power switches in electronic applications. |
| Advantage: The trench MOSFET gate structure is formed in a trench which minimizes cell pitch and enables both a reduction in on-state resistance and total area. The buried field shield can be implemented by selective area ion implantation to create a region which not only protects the dielectric at the bottom of the trench but also forms a highly doped contact region at the semiconductor surface which serves as the body contact. |
| Novelty: The III-V compound semiconductor trench metal oxide semiconductor field effect transistor (MOSFET) has a buried field shield electrically connected to a body layer and terminates at a source layer, a drain contact to a substrate, a gate contact that partially fills a gate trench on a gate dielectric layer, and a source contact to the source layer. A body contact is made through the source contact, and contacts the body layer. The body layer is embedded in and terminated in a drift layer. A gate trench is defined by sidewalls and a bottom. |
| Filed: 6/2/2022 |
| Application Number: US17830624A |
| Tech ID: SD 15545.1 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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