Patent ID: 7999314
Filing Date: 2011-08-16
Classification: H01L

Abstract:
1. A semiconductor device comprising: an n-conductive type semiconductor substrate having a main side and a rear side, and including a trench type MOS transistor cell and a diode cell; a p-conductive type layer arranged over a main side surface portion of the n-conductive type semiconductor substrate, and having an impurity concentration which decreases from the main side toward the rear side; a main side n-conductive type region having an impurity concentration higher than an impurity concentration of the substrate, and arranged over a surface portion of the p-conductive type layer; a rear side n-conductive type layer arranged over a rear side surface portion of the n-conductive type semiconductor substrate; a main side p-conductive type region having an impurity concentration higher than the impurity concentration of the p-conductive type layer, and arranged in a surface portion of the p-conductive type layer; a first trench which reaches the n-conductive type semiconductor substrate and penetrates the main side n-conductive type region and the p-conductive type layer; a first electrode layer embedded in the first trench through an insulating film, and providing a gate electrode of the trench type MOS transistor cell; a second electrode layer arranged over the main side of the n-conductive type semiconductor substrate, electrically coupled with the main side n-conductive type region and the p-conductive type layer, and providing both a source electrode of the trench type MOS transistor cell and an anode electrode of the diode cell; a third electrode layer arranged over the rear side of the n-conductive type semiconductor substrate, electrically coupled with the rear side n-conductive type layer, and providing both a drain electrode of the trench type MOS transistor cell and a cathode electrode of the diode cell; and a second trench which reaches an inside of the p-conductive type layer and does not penetrate the p-conductive type layer, wherein the second trench penetrates the main side n-conductive type region and the main side p-conductive type region, wherein the second electrode layer is embedded in the second trench, and the second electrode layer is electrically coupled with a first part of the p-conductive type layer at a bottom of the second trench, wherein an impurity concentration of the first part of the p-conductive type layer is lower than an impurity concentration of a second part of the p-conductive type layer, and wherein the second electrode layer is electrically coupled with the main side p-conductive type region at a sidewall of the second trench.