Study of Ultra-High Voltage BCD Process with Gate Oxide Thinning

High voltage gate driver ICs, which have the advantages of short response time, low power consumption, high integration and high reliability, are widely used in motor drives, automotive electronics, electronic ballasts, switching mode power supplies and other fields. Due to the applied voltage usually above 500V, the gate oxide thickness of the device is thick, usually higher than 400A. This paper investigates the possibility of using a thinned gate oxide thickness in an ultra-high voltage BCD process. With a thinner gate oxide, lower threshold voltage, higher saturation current and lower on-resistance can be achieved. But the side-effect is that the breakdown voltage of the device will decrease. This paper also studies how to improve the breakdown voltage of the device after using thinner gate oxide, and positive progress has been made.