Achievement of high gain in a planar heterojunction bipolar transistor with lateral current flow

The authors have demonstrated transistor action in an L-HBT (lateral heterojunction bipolar transistor) device with multiple, quantum sized base channels. The small size of the individual channels has made it possible to increase the steepness of the alloy composition grading at the emitter-base junction of the transistor when the emitter is formed by Si diffusion disordering. It is well known that this interfacial grading must be optimized in order to achieve the maximum transistor device performance. As a result of these and other design modifications, transistor action with a maximum gain beta well in excess of 200 was achieved. These gain values demonstrate the practicality of transistor devices of the L-HBT design.