Current gain and low-frequency noise of symmetric lateral bipolar junction transistors on SOI

This paper presents a comprehensive study of symmetric lateral bipolar junction transistors (LBJTs) fabricated on SOI substrate using a CMOS-compatible process; LBJTs find many applications including being a local signal amplifier for silicon-nanowire sensors. Our LBJTs are characterized by a peak gain $(\beta)$ over 50 and low-frequency noise two orders of magnitude lower than what typically is of the Si02/Si interface for a MOSFET. $\beta$ is found to decrease at low base current due to recombination in the space charge region at the emitter-base junction and at the surrounding Si02/Si interfaces. This decrease can be mitigated by properly biasing the substrate.