| 摘要 |
PURPOSE:To obtain a low-loss composite semiconductor device being easy to drive and having a large breakdown strength, by making the insulating film thickness of second and third gates larger than the insulating film thickness of a first gate. CONSTITUTION:MOSTQ1 to be a main switch is composed of the respective electrode of a source 16, a gate 13 and a drain 20, and an n-channel MOSTQ2 for drive is composed of the respective electrodes of a source 18, a gate 15 and the drain 20, while a p-channel MOSTQ3 for drive is composed of the respective electrodes of a source 4, a gate 14 and a drain 18. The present structure is characterized in that the film thickness of gate oxide films 11 and 12 under the gate electrodes of Q2 and Q3 which are connected directly to gate terminals is larger than that of a gate oxide film 10 of Q1 which is to be a main switch. As the result, the breakdown strength of the gate oxide films of Q2 and Q3 can be maintained at a large value with the ON resistance of Q1 lowered so as to attain a low loss. Concretely, an electrostatic breakdown strength (200pF charged capacity) of 300V or above can be obtained under the condition of voltage resistance 60V and ON resistance 0.1OMEGA. |
