| US 7,482,285 B2 | ||
| Dual epitaxial layer for high voltage vertical conduction power MOSFET devices | ||
| Zhijun Qu, Torrance, Calif. (US); and Kenneth Wagers, Los Angeles, Calif. (US) | ||
| Assigned to International Rectifier Corporation, El Segundo, Calif. (US) | ||
| Filed on Oct. 17, 2002, as Appl. No. 10/274,644. | ||
| Application 10/274644 is a continuation of application No. 09/329156, filed on Jun. 09, 1999, abandoned. | ||
| Prior Publication US 2003/0034519 A1, Feb. 20, 2003 | ||
| Int. Cl. H01L 21/33 (2006.01); H01L 21/3205 (2006.01); H01L 21/8238 (2006.01); H01L 21/336 (2006.01) | ||
| U.S. Cl. 438—761 [438/212; 438/268; 438/587] | 6 Claims |

| 1. A method of producing a MOS-gated semiconductor device, comprising:
providing a dual epitaxial junction-receiving layer, including: providing a first epitaxially grown layer of a first conductivity
type and a first resistivity over a substrate; and
providing a second epitaxially grown layer of the first conductivity type and a second resistivity over said first epitaxially
grown layer, said second resistivity being different from said first resistivity;
forming body regions of a second conductivity type in said second epitaxially grown layer, each of the body regions having
a depth that is less than the thickness of said second epitaxially grown layer, said body regions forming PN junctions with
said second epitaxially grown layer to obtain a device breakdown voltage for said device;
forming source regions of said first conductivity type in said body regions; and
forming a gate structure over said second epitaxially grown layer,
wherein selections of a concentration of dopants and a thickness of each said first and said second epitaxially grown layers
so as to obtain a device breakdown voltage and a total thickness of the first and second expitaxiallv grown layers involve
a comparison in electric field distribution with a power MOSFET having a same structure as that of said device, except that
the power MOSFET only has a single epitaxial junction-receiving layer therein, said single epitaxial junction-receiving layer
being of said first conductivity type and having a same concentration of dopants as that in said first epitaxially grown layer
and receiving body regions same as the body regions in said device, and,
wherein said device breakdown voltage is the same as a device breakdown voltage of the power MOSFET and wherein said total
thickness is less than the thickness of said single epitaxial junction-receiving layer.
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