L fast-fabrication process for high speed bipolar analog large scale integrated circuits

Abstract From the Canadian patent

Abstract of the Disclosure A fabrication process for integrated circuits having linear bipolar transistors and other circuit elements. The process defines collector contact 32 base 34, and isolation 36 regions in one masking operation. Subsequent masking layers of photoresist 40, 42, 46 are used to shield selected regions during implantation of exposed regions. Circuit density is improved through the use of aluminum doped isolation regions 36. The base region is doped in a single ion implantation step, which is followed by low temperature deposition of a covering oxide layer 48.