Bipolarity Bipolar Device
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Fig. 1 is a three-dimensional view of a cross-section of the bipolarity bipolar device showing its formation in an N-type epitaxial layer having P-type isolation regions 1 defining an N-type epitaxial island and an N type subcollector 3. A P-type base diffusion 12 having an L-shape is deposited in the N-type epitaxial region and an N-type emitter 10 is formed in the "foot" of the L-shaped base region. The length of the vertical stem of the L-shaped base is designed to form a desired resistance R1 between the emitter's position and the base contact at the top of the vertical stem of the L-shape. A P+ diffusion 5 is formed at the same time as is the base diffusion 12 and will serve as the source of a P channel FET device 7. shown also in the circuit schematic diagram of Fig. 2.