设计并制作了18 mm间隙的半绝缘GaAs光导开关,开关芯片采用标准半导体工艺制作并封装在陶瓷基板上。测试了光导开关在20 kV工作电压、1 kA工作电流时,不同重复频率工作的开关寿命,结果表明,开关寿命4 000次～7 000次,且随着重复频率的提高,开关寿命有所降低。初步分析了导致开关失效的原因为热损伤,包括局部发热导致的连接损伤和材料损伤以及整体发热导致的暗态电阻下降。

Photoconductive semiconductor switch(PCSS) with a gap of 18 mm was fabricated from semi-insulating GaAs. Lifetime tests of the PCSS were performed at different repetition rate. Accumulation and dissipation of heat in the switch’s running process was analyzed with the test results. Heat accumulation has an important effect on the lifetime of the switch. When the accumulation power of heat is higher than the dissipation power of heat,the temperature of the chip rises and the resistence reduces. As a results,the leak current increased as high as the charge current of the capacitor and the switch can’t sustain a bias voltage,and the photocurrent decreases as the switch is running. In addition,the damage at the ohm contact is also a heat damage because of a high field at the electrode region when the switch is triggered.