The effect of optical injection on the gain and high frequency performance of AlGaAs/GaAs heterojunction bipolar transistor

• Main Author: Lee, Chia-Nan
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/3829

A comprehensive, one-dimensional, analytical model of the graded-base AlGaAs/GaAs heterojunction bipolar transistor is presented, and used to examine the influence of optical injection on the DC and high-frequency performance of a device with a conventional pyramidal structure. Absorption is limited to the base and collector regions because of the window effect of the wider bandgap emitter. Grading is considered by varying the A l mole fraction x linearly across the base to a value of zero at the base-collector boundary. Recombination in the space-charge and neutral regions of the device is modeled by considering Shockley-Read-Hall, Auger and radiative processes. Experimental devices were obtained from the Communications Research Centre, Ottawa and packaged by the author at the Alberta Microelectronics Centre and the Telecommunications Research Laboratory, Edmonton. The packaged devices were tested to evaluate the DC and high-frequency performances. Comparisons between predictions of the model and experimental data from a packaged device are presented. Optical injection is observed to improve the DC and high-frequency characteristics of the device.