Trench type insulated gate mos semiconductor device

A trench gate type insulated gate bipolar transistor comprising:

• a semiconductor substrate of a first conductivity type to be a drift layer;
• a base region of a second conductivity type selectively formed on one of the principal surfaces of the semiconductor substrate of the first conductivity type;
• an emitter region of the first conductivity type selectivity formed on the surface of the base region of the second conductivity type;
• a plurality of straight-line-like trenches arranged in parallel to form a planar pattern of a plurality of parallel straight lines, each trench being formed from the surface of the emitter region of the first conductivity type to reach the semiconductor substrate of the first conductivity type while penetrating the base region of the second conductivity type;
• a gate electrode formed in each of the trenches with a gate insulator film interposed between;
• an emitter electrode making contact with both of the surfaces of the base region of the second conductive type and the emitter region of the first conductivity type;
• a collector layer of the second conductivity type formed on the other principal surface of the semiconductor substrate of the first conductivity type;
• a collector electrode in contact with the collector layer;
• and
• a field stop layer of the first conductivity type provided between the drift layer as the semiconductor substrate of the first conductivity type and the collector layer of the second conductivity type, the field stop layer having an impurity concentration higher than that of the drift layer and formed with a diffusion depth from the other principal surface being 100 μm or more;
• wherein the transistor is provided with a structure in which the base region of the second conductivity type is divided into a first region and a second region by a plurality of the trenches, the surface of the base region in the first region makes the emitter electrode contact directly thereto, and the surface of the base region in the second region makes the emitter electrode contact thereto with an insulator film interposed between to allow a part of a current to flow to the emitter electrode through the second region formed so as to have resistance of less than 100 mΩ/cm2 per unit area.

A trench gate type insulated gate bipolar transistor comprising:

• a semiconductor substrate of a first conductivity type to be a drift layer;
• a base region of a second conductivity type selectively formed on one of the principal surfaces of the semiconductor substrate of the first conductivity type;
• an emitter region of the first conductivity type selectivity formed on the surface of the base region of the second conductivity type;
• a plurality of straight-line-like trenches arranged in parallel to form a planar pattern of a plurality of parallel straight lines, each trench being formed from the surface of the emitter region of the first conductivity type to reach the semiconductor substrate of the first conductivity type while penetrating the base region of the second conductivity type;
• a gate electrode formed in each of the trenches with a gate insulator film interposed between;
• an emitter electrode making contact with both of the surfaces of the base region of the second conductive type and the emitter region of the first conductivity type;
• a collector layer of the second conductivity type formed on the other principal surface of the semiconductor substrate of the first conductivity type;
• a collector electrode in contact with the collector layer;
• and
• a field stop layer of the first conductivity type provided between the drift layer as the semiconductor substrate of the first conductivity type and the collector layer of the second conductivity type, the field stop layer having an impurity concentration higher than that of the drift layer and formed with a diffusion depth from the other principal surface being 100 μm or more;
• wherein the emitter electrode makes direct contact with the surface of each base region of the second conductivity positioned between the trenches adjacent to each other;
• and
• wherein, when avalanche breakdown occurs in a turned-off state, a distance between the collector layer and an end of a space charge region is at least 100 μm or more, the space charge region expanding toward the collector layer from a p-n junction formed between the base region of the second conductivity type and the drift layer.