Sidewall thickness and overhanging length are crucial parameters in super self-aligned technology for SiGe HBT’s. The two parameters have certain influence on the parasitic effect and junction area of the device, thus affecting the current amplifying factor β and characteristic frequency f_t. An optimized structure of super self-aligned SiGe HBT is described based on our research of different super self-aligned technologies. Simulations are made on sidewall and overhanging in the super self-aligned structur...