Semiconductor device with protective means against overheating

A semiconductor integrated circuit device comprising:

• a semiconductor body;
• a vertical type power MOS transistor element formed in said semiconductor body;
• a semiconductor region located in the substantially center part of one surface region of said semiconductor body, said region being a different conductivity type from said semiconductor body;
• a heat-sensitive element including at least one diode element formed by a PN junction being formed in a polycrystalline silicon semiconductor layer on an insulation film formed on said semiconductor region, said heat-sensitive element detecting the temperature of said semiconductor body rising due to the heat generated by said power MOS transistor element;
• and
• control means formed on at least one of the semiconductor region formed in said one surfact region of said semiconductor body and the polycrystalline silicon semiconductor layer formed in said insulation film, said control means including a conductive member which electrically connects said control means to said at least one diode element, for protecting said power MOS transistor element from thermal breakdwon according to the level of a forward drop voltage generated in said at least one diode element.

A semiconductor integrated circuit device comprising:

• a semiconductor body;
• a semiconductor element formed in said semiconductor body;
• a semiconductor region formed in one surface region of said semiconductor body, said region being a different conductivity type from said semiconductor body;
• a heat-sensitive element formed in a polysrystalline silicon semiconductor layer on an insulation film formed on said semiconductor region, said heat-sensitive element having a plurality of PN junctions including each of a pair of highly doped regions and lowly doped regions, and further including a conductive member which connects said plurality of PN junctions to each other in series in the same polar direction so as to form a plurality of diode elements, the impurity concentration of said slowly doped region being 1.times.10.sup.19 cm.sup.-3 or more, and the temperature of said conductive body generated by said semiconductor element being detected by said plurality of diodes;
• and
• a control element, formed in at least a portion of said semiconductor region being formed on said one surface region of said semiconductor body and electrically connected to said plurality of diodes through the conductive member, for controlling said semiconductor element according to the level of a forward drop voltage generated on said diode elements, thereby protecting the semiconductor element from thermal breakdown.