Trench MOSFET having improved breakdown and on-resistance characteristics
US6084264A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 25, 1998 |
| Grant date | Jul 4, 2000 |
| Priority date | — |
| Expiry date | Nov 25, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D62/105
Abstract
A trench MOSFET is formed in a structure which includes a P-type epitaxial layer overlying an N+ substrate. An N drain region is implanted through the bottom of the trench into the P-epitaxial layer, and after a diffusion step extends between the N+ substrate and the bottom of the trench. The junction between the N drain region and the P-epitaxial layer extends between the N+ substrate and a sidewall of the trench. In some embodiments the epitaxial layer can have a stepped doping concentration or a threshold voltage adjust implant can be added. Alternatively, the drain region can be omitted, and the trench can extend all the way through the P-epitaxial layer into the N+ substrate. A MOSFET constructed in accordance with this invention can have a reduced threshold voltage and on-resistance and an increased punchthrough breakdown voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.