Requirements on CD and overlay for 200 GHz QSA SiGe:C HBTs

Abstract

In this paper, we investigate the sensitivity of the quasi self-alignment (QSA) architecture to CD variation and alignment, resulting in a set of requirements on lithography capability imposed by the electrical performance of the device. We show that these requirements can be met without difficulty using present-day step and scan tools, so long as some precautions are taken in terms of alignment strategy. We show that the base current, current gain and BV/sub EBO/ are the DC parameters of the HBT device most sensitive to misalignment.