Process Sensitivity of Depleted Base Bipolar Transistors (BSIT)

An important factor in testing the applicability of devices for VLSI circuits is the tolerance of their electrical characteristics to process variations. Conventional MOS transistors produce currents which depend linearly on device geometry. Scaling of these devices is well understood to first order and can be accomplished without introducing additional process sensitivities. The current of conventional bipolar junction transistors (BJT) is linearly related to the surface area and current gains are independent of device geometry. A major reason why both of these devices are successfully applied in small geometry VLSI circuits is their tolerance to process variations.