Fabrication of Base Region of a Transistor Using Two Ion Implantation Steps
Original Publication Date: 1978-Jul-01
Included in the Prior Art Database: 2005-Feb-21
In conventional processes for fabricating the base region of the transistor, the peak impurity concentration is usually compensated, thereby not contributing to conductivity. However, the P concentration is potentially detrimental to the lattice perfection, thereby making it susceptible to leakage by the formation of defects. With ion implantation, however, the intrinsic base region may be implanted in situ. Because the required impurity concentration in the intrinsic region is low, the number of defects is also low. A second implantation of high dosage, low energy impurities is then used to form the extrinsic, or base contact, region.