Implanted collector profile optimization in a SiGeHBT process

Optimization of implanted collector doping profiles for a high-speed, low-v oltage SiGe HBT process has been investigated experimentally and by device simulations. A low-energy antimony implantation has been combined with a st andard selectively implanted collector using phosphorous, to achieve improv ed control of the collector doping profile. The simulations indicate that t he narrow n-type doping peak formed by the antimony implantation allows the cut-off frequency f(T) to be increased without degrading the collector emi tter breakdown voltage BVCEO. The fabricated devices demonstrate a highest f(T) of 60 GHz. Depending on the collector profile BVCEO values between 1.5 and 2 V were obtained. (C) 2001 Elsevier Science Ltd. All rights reserved.