Power trench MOSFETs having SiGe/Si channel structure
US7504691B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 2006 |
| Grant date | Mar 17, 2009 |
| Priority date | — |
| Expiry date | Oct 22, 2026 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P70/50
Abstract
Devices, methods, and processes that improve immunity to transient voltages and reduce parasitic impedances. Immunity to unclamped inductive switching events is improved. For example, a trench-gated power MOSFET device having a SiGe source is provided, where the SiGe source reduces parasitic npn transistor gain by reducing hole current in the body or well region, thereby decreasing the likelihood of a latch-up condition. A trench-gated power MOSFET device having a SiGe body or well region is also provided. A SiGe body reduces hole current when the body diode is turned on, thereby reducing reverse recovery power losses. Other device characteristics are also improved. For example, parasitic gate impedance can reduced through the use of a poly SiGe gate. Also, channel resistance can be reduced through the use of a SiGe layer near the device's gate and a thick oxide region can be formed under the trench gate to reduce gate-to-drain capacitance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.