FABRICATION METHOD, VARACTOR, AND INTEGRATED CIRCUIT

摘要

A method in the fabrication of an integrated bipolar circuit for forming a p/n-junction varactor is disclosed. The method featuring the steps of providing a p-doped substrate (10; 10, 41); forming a buried n+-doped region (31) in the substrate; forming in the substrate an n-doped region (41) above the buried n+-doped region (31); forming field isolation (81) around the n-doped region (41); multiple ion implanting the n-doped region (41); forming a p+-doped region (151) on the n-doped region (41); forming an n+-doped contact region to the buried n+-doped region (31), the contact region being separated from the n-doped region (41); and heat treating the hereby obtained structure to set the doping profiles of the doped regions. The multiple ion implantation of the n-doped region (41); the formation of the p+-doped region (151); and the heat treatment are performed to obtain a hyper-abrupt p+/n-junction within the n-doped region (41).