05801417 is referenced by 133 patents and cites 17 patents.

A recessed gate power MOSFET is formed on a substrate (20) including a P-body layer (26), N-drain layer (24) and optional P+ layer (22) for IGBT. A trenching protective layer (30) formed on the substrate upper surface (28) is patterned to define exposed areas (46) as stripes or a matrix, and protected areas. Sidewall spacers (44) of predetermined thickness (52) with inner surfaces (48) contact the protective layer sidewalls. A first trench (50) is formed in substrate areas (46) with sidewalls aligned to the sidewall spacer outer surfaces (47) and extending depthwise through the P-body layer (26) to at least a predetermined depth (56). Gate oxide (60) is formed on the trench walls and gate polysilicon (62) refills the trench to a level (64) near substrate upper surface (28). Oxide (68) between sidewall spacers (44) covers polysilicon (62). Removing the protective layer exposes upper substrate surface (28') between spacer inner surfaces (48). This area is doped to form a source layer (72) atop the body layer (26') and then trenched to form a second trench (80) having sidewalls aligned to the spacer inner surfaces. Second trench (80) defines vertically-oriented source and body layers (86, 90) stacked along gate oxide layer (60) to form vertical channels on opposite sides of second trench (80). Layers (86, 90) have a lateral thickness (88) established by the predetermined spacing of the inner and outer surfaces of the sidewall spacers. Source conductor (94) in the second trench contacts the N-source and P-body layers, and an enhanced P+ region at the base of the second trench.

Title
Self-aligned power MOSFET device with recessed gate and source
Application Number
194874
Publication Number
5801417
Application Date
August 13, 1993
Publication Date
September 1, 1998
Inventor
Theodore O Meyer
Bend
OR, US
Douglas A Pike Jr
Bend
OR, US
John W Mosier II
Bend
OR, US
Dah Wen Tsang
Bend
OR, US
Agent
Marger Johnson McCollom & Stolowitz P C
Assignee
Advanced Power Technology
OR, US
IPC
H01L 29/94
H01L 29/76
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