Aiming　at　improving　accuracy　of　photoetching　technology　in　conventional　double-mesa　process　for　SiGe　heterojunction　bipolar　transistor　(HBT),　this　paper　introduced　buried-metal　layers　and　developed　silicon　based　buried-metal　self-aligned　process　in　order　to　increase　the　mesa　area　utilization　efficiency.　Novel　process　has　advantages　of　smaller　junction　area,　larger　metal-semiconductor　contact　area　and　fewer　pinhole　fabrication　defects,　with　no　increase　of　fabrication　difficulties　or　advancement　of　photolithography　equipment.