A self-consistent regional approach to computer-aided transistor design

The classical transistor theory developed by Shockley and later extended to high currents by Webster is based on division of the transistor into physically defined regions. Details of the electron density and electric field are limited to the base region. Inherent in the classical theory is a monotonically decreasing injected-minority-carrier density in the base region. More complex injected-carrier-density profiles have been shown to exist by Lindmayer and Wrigley for the junction diode. In all of these approaches base widening is prevented by the assumption of operation under "perfect sink conditions."