Compact Models for Integrated Circuit Design

11

Bipolar Junction Transistor Compact Models

11.1  Introduction

As described in Chapters 4 and 5, the pn-junctions are integral part of a MOSFET (metal-oxide-semiconductor field-effect transistor) device structure as the source and drain regions. Under the appropriate biasing condition of a MOSFET device, the source of the source-substrate pn-junction provides a steady supply of mobile carriers to form a conducting channel from the source to drain and the drain of the drain-substrate pn-junction collects the mobile carriers generating drain current. Two back-to-back pn-junctions form a bipolar junction transistor (BJT). BJTs are very often used in VLSI (very-large-scale-integrated) circuits. Therefore, a basic understanding of BJT modeling ...