The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 17, 2009
Filed:
Aug. 31, 2006
Chanho Park, Sandy, UT (US);
Qi Wang, Sandy, UT (US);
Chanho Park, Sandy, UT (US);
Qi Wang, Sandy, UT (US);
Fairchild Semiconductor Corporation, South Portland, ME (US);
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.