SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To provide a semiconductor device capable of leveling heats of respective semiconductor elements without regulating the shape, interval and size of the elements. SOLUTION: The semiconductor device 11 comprises a semi-insulating board 12, heterojunction bipolar transistors (abbreviated: HBT) 71 to 78 connected in parallel, an air gap region 21 with a bottom formed by opening upward at an interval at one end side of the HBT 71, and an air gap region 22 formed similarly at the other end side of the HBT 78. Thus, the temperature in the device 11 can be made uniform, without having to raise only the central part in the device to a high temperature by the heat generated in the device 11. The fatal damage to the device 11 is prevented, and the device can be operated stably.