MOSFET having buried shield plate for reduced gate/drain capacitance
First Claim
1. A field effect transistor having reduced gate to drain capacitance comprising:
- a semiconductor body having a major surface,a source region of first conductivity-type abutting said surface,a drain region of said first conductivity-type abutting said surface and spaced from said source region with a channel therefrom,a gate overlying said channel and part of said drain and insulated from the channel and the drain by a dielectric material, anda shield plate positioned beneath said gate and between said gate and said drain and insulated from the gate and the drain by a dielectric material.
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Accused Products
Abstract
Gate to drain capacitance in a lateral DMOS and vertical DMOS field effect transistor is minimized by providing a conductive shield plate under the gate and between the gate and the drain of the transistor. In operation, the shield plate is preferably connected to a DC voltage potential and coupled to AC ground for RF power applications. The shield plate is readily fabricated in a conventional polysilicon gate process by adding one additional polysilicon deposition (or other suitable material), one additional mask, and one additional etch step. The shield plate can include a raised portion which provides lateral capacitive isolation between the gate and the drain. Alternatively, a shield contact can be provided above the shield plate and between the gate and drain to provide lateral isolation.
153 Citations
15 Claims
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1. A field effect transistor having reduced gate to drain capacitance comprising:
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a semiconductor body having a major surface, a source region of first conductivity-type abutting said surface, a drain region of said first conductivity-type abutting said surface and spaced from said source region with a channel therefrom, a gate overlying said channel and part of said drain and insulated from the channel and the drain by a dielectric material, and a shield plate positioned beneath said gate and between said gate and said drain and insulated from the gate and the drain by a dielectric material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification