| US 7,601,596 B2 | ||
| Semiconductor device with trench transistors and method for manufacturing such a device | ||
| Markus Zundel, Egmating (Germany); Franz Hirler, Isen (Germany); Rudolf Zelsacher, Klagenfurt (Austria); and Erwin Bacher, Villach (Austria) | ||
| Assigned to Infineon Technologies Austria AG, Villach (Austria) | ||
| Filed on Nov. 16, 2006, as Appl. No. 11/600,422. | ||
| Prior Publication US 2008/0116511 A1, May 22, 2008 | ||
| Int. Cl. H01L 21/336 (2006.01) | ||
| U.S. Cl. 438—268 [438/134; 438/246; 438/267; 438/270; 438/275; 257/E21.651] | 8 Claims |
| 1. A method for manufacturing a semiconductor device comprising:
forming trenches in a first side of a semiconductor material;
forming a thick oxide layer on the trenches and on the first side;
masking a part of the first side and the trenches using a first mask and leaving another part of the first side and a part
of at least one of the trenches unmasked;
doping the semiconductor material by implantation through the thick oxide layer while the first mask is present; and
removing at least part of the thick oxide layer while the first mask remains.
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