| US 7,550,787 B2 | ||
| Varied impurity profile region formation for varying breakdown voltage of devices | ||
| Douglas D. Coolbaugh, Essex Junction, Vt. (US); Louis D. Lanzerotti, Charlotte, Vt. (US); Bradley A. Orner, Fairfax, Vt. (US); Jay S. Rascoe, Underhill, Vt. (US); David C. Sheridan, Williston, Vt. (US); and Stephen A. St. Onge, Colchester, Vt. (US) | ||
| Assigned to International Business Machines Corporation, Armonk, N.Y. (US) | ||
| Filed on May 31, 2005, as Appl. No. 10/908,884. | ||
| Prior Publication US 2006/0270203 A1, Nov. 30, 2006 | ||
| Int. Cl. H01L 29/737 (2006.01) | ||
| U.S. Cl. 257—197 [257/565; 257/E29.174] | 6 Claims |
| 1. A semiconductor device comprising:
a substrate;
a first subcollector having a first impurity at a first depth in the substrate; and
a first collector having a second impurity at a second depth different than the first depth in the substrate,
wherein an impurity profile of the second impurity that is within the first collector comprises a high impurity concentration
that extends from near center of the first collector to a lateral edge of the first collector, and a low impurity concentration
near the center of the first collector, and wherein the concentration of the second impurity is the same throughout the first
collector region.
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