Patent ID: 8129780
Filing Date: 2012-03-06
Classification: H01L

Abstract:
1. A semiconductor device comprising: (a) an active cell which causes a load current to flow therethrough; (b) a sense cell which detects a magnitude of the load current flowing through the active cell; and (c) an inactive cell which separates the active cell and the sense cell from each other, wherein each of the active cell, the sense cell and the inactive cell includes: (d1) a first semiconductor region of a first conduction type formed over a first surface of a semiconductor substrate corresponding to the first conduction type; (d2) a second semiconductor region of a second conduction type corresponding to a conduction type opposite to the first conduction type, said second semiconductor region being formed over the first semiconductor region; (d3) a trench which penetrates the second semiconductor region to reach the first semiconductor region and is formed so as not to reach the semiconductor substrate; (d4) a first insulating film formed in parts of a bottom face of the trench and a side surface thereof; (d5) a dummy gate electrode formed inside the trench via the first insulating film; (d6) a second insulating film formed so as to cover an upper portion of the dummy gate electrode; (d7) a gate electrode provided over the second insulating film and formed inside the trench; (d8) a gate insulating film formed between the side surface of the trench and the gate electrode; and (d9) a drain region comprising the semiconductor substrate corresponding to the first conduction type, and wherein (d10) each of the active cell and the sense cell further has a source region formed in alignment with the trench and comprising a semiconductor region of the first conduction type formed over the second semiconductor region, whereas the inactive cell does not include the source region, wherein the dummy gate electrode and the gate electrode are electrically coupled to each other, wherein the trench with the dummy gate electrode and the gate electrode embedded therein is formed in plural form so as to be arranged in a first direction of the semiconductor substrate, and wherein the respective trenches are formed so as to extend in a second direction orthogonal to the first direction, wherein first trenches of the respective trenches which extend in the second direction through an active cell forming area formed with the active cell, a sense cell forming area formed with the sense cell and an inactive cell forming area formed with the inactive cell, exist, wherein gate electrodes embedded in the first trenches extending in the second direction through the active cell forming area, the sense cell forming area and the inactive cell forming area function as a gate electrode of the active cell in the active cell forming area, function as a gate electrode of the sense cell in the sense cell forming area, and function as a gate electrode of the inactive cell in the inactive cell forming area, respectively, and wherein the first trenches adjacent to one another are coupled by blocking trenches extending in the first direction.