Sub-20 psec ECL circuits with 50 GHz fmax self-aligned SiGe HBTs

This paper describes a high fmax self-aligned SiGe heterojunction bipolar transistor (HBT) technology which is based on the self-aligned selective epitaxial growth technology including Ge graded profile and link-base engineering using a BSG sidewall structure. The HBT has a Super Self-aligned Selectively grown SiGe Base (SSSB) structure. Base profile design and a 2-step annealing technique have realized a f/sub T/ of 51 GHz and low sheet resistance at the link-base region, and furthermore have accomplished fmax of as high as 50 GHz. ECL circuits of 19 psec gate delay have been achieved by using this SiGe HBT technology. >