The sensitivity of transistor gain to processing variations in an all implanted bipolar technology

The integrated circuit technology described here has evolved from one incorporating a transistor with a single base implant providing both the active and inactive base regions of the transistor, to one which employs two separate base implants for each region. The sensitivity of the transistor gain to variations in pertinent processing steps is discussed for each procedure. It is found that the double base implantation procedure provides more flexibility in the tailoring and control of transistor gain.