MOS-gated device having a buried gate and process for forming same
First Claim
1. An improved trench MOS-gated device comprising:
- a substrate with a surface source region;
a trench through the source region to define vertical surfaces in the source adjacent the trench;
a drain disposed beneath the trench;
said trench at least partially lined with insulating material, it lower portion partially filled with conductive material, and its upper portion partially filled with insulating material to leave at least a portion of the vertical surfaces of the source adjacent the surface of the substrate without insulation;
a metal contact layer on the substrate surface of the source and on the vertical surface of the source adjacent the surface.
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Accused Products
Abstract
An improved trench MOS-gated device comprises a monocrystalline semiconductor substrate on which is disposed a doped upper layer. The upper layer includes at an upper surface a plurality of heavily doped body regions having a first polarity and overlying a drain region. The upper layer further includes at its upper surface a plurality of heavily doped source regions having a second polarity opposite that of the body regions. A gate trench extends from the upper surface of the upper layer to the drain region and separates one source region from another. The trench has a floor and sidewalls comprising a layer of dielectric material and contains a conductive gate material filled to a selected level and an isolation layer of dielectric material that overlies the gate material and substantially fills the trench. The upper surface of the overlying layer of dielectric material in the trench is thus substantially coplanar with the upper surface of the upper layer. A process for forming an improved MOS-gate device provides a device whose gate trench is filled to a selected level with a conductive gate material, over which is formed an isolation dielectric layer whose upper surface is substantially coplanar with the upper surface of the upper layer of the device.
23 Citations
19 Claims
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1. An improved trench MOS-gated device comprising:
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a substrate with a surface source region;
a trench through the source region to define vertical surfaces in the source adjacent the trench;
a drain disposed beneath the trench;
said trench at least partially lined with insulating material, it lower portion partially filled with conductive material, and its upper portion partially filled with insulating material to leave at least a portion of the vertical surfaces of the source adjacent the surface of the substrate without insulation;
a metal contact layer on the substrate surface of the source and on the vertical surface of the source adjacent the surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19)
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16. The device of claim 16 wherein cells in said closed-cell cellular topology have a square configuration or a hexagonal configuration.
Specification