High voltage MOSFET with geometrical depletion layer enhancement
First Claim
1. A field-effect semiconductor device comprising a semiconductor body including a channel-accommodating region of a second conductivity type between source and drain regions of an opposite first conductivity type, wherein a body portion separates the channel-accommodating region from the drain region, both the body portion and the source and drain regions extending adjacent to a surface of the body, the body portion includes a drift region of the first conductivity type for current flow of charge carriers of the first conductivity type to the drain region from a conduction channel in the channel-accommodating region in a conducting mode of operation of the device, and the body portion also includes relief regions of the second conductivity type which are present in the drift region adjacent to the surface, the relief regions and the drift region of the body portion together providing a space charge region under the spread of a depletion layer from the channel-accommodating region to the drain region when a blocking voltage is present between the channel-accommodating region and the drain region in one mode of operation of the device, wherein the semiconductor device comprises a concentric arrangement of the source and drain regions at the surface of the body, in which the drain region extends at least partially around the body portion and the source region, in which the spacing between neighbouring relief regions increases from the channel-accommodating region towards the drain region, and in which the width of at least some of the relief regions decreases towards the drain region.
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Accused Products
Abstract
In a field-effect semiconductor device, for example a power MOSFET, a body portion separates a channel-accommodating region from a drain region at a surface of a semiconductor body. This body portion includes a drift region which serves for current flow of charge carriers of a first conductivity type from the conduction channel to the drain region, in a conducting mode of the device. Instead of being a single region, the body portion also includes field-relief regions of the second conductivity type, which are depleted together with the drift region in a voltage blocking mode of the device to provide a voltage-carrying space-charge region. The drain region extends at least partially around the body portion at the surface, and the relief regions are located radially in this body portion.
140 Citations
9 Claims
- 1. A field-effect semiconductor device comprising a semiconductor body including a channel-accommodating region of a second conductivity type between source and drain regions of an opposite first conductivity type, wherein a body portion separates the channel-accommodating region from the drain region, both the body portion and the source and drain regions extending adjacent to a surface of the body, the body portion includes a drift region of the first conductivity type for current flow of charge carriers of the first conductivity type to the drain region from a conduction channel in the channel-accommodating region in a conducting mode of operation of the device, and the body portion also includes relief regions of the second conductivity type which are present in the drift region adjacent to the surface, the relief regions and the drift region of the body portion together providing a space charge region under the spread of a depletion layer from the channel-accommodating region to the drain region when a blocking voltage is present between the channel-accommodating region and the drain region in one mode of operation of the device, wherein the semiconductor device comprises a concentric arrangement of the source and drain regions at the surface of the body, in which the drain region extends at least partially around the body portion and the source region, in which the spacing between neighbouring relief regions increases from the channel-accommodating region towards the drain region, and in which the width of at least some of the relief regions decreases towards the drain region.
Specification