AlGaAs/GaAs heterojunction phototransistor with a double delta-doped base grown by MOVPE

Heterojunction bipolar phototransistors (HPTs), based on GaAs technology, are widely used in the optoelectronic-integrated circuit (OEIC) [H.T. Lin, D.H. Rich, A. Larsson, J. Appl. Phys. 79 (1996) 8015 [1]; Lin Chien-chung, M. Wayne, J.S. Harris Jr., F. Sugihwo, Appl. Phys. Lett. 76 (2000) 1188 [2]]. They exhibit a large optical gain and a negligible noise level at low bias voltages. The presented work describes the fabrication and device characteristics of n-p-n AlGaAs/GaAs heterojunction phototransistor with a double Zn delta-doped GaAs base region (2delta-Zn-AlGaAs/GaAs HPT). Such construction of the transistor allows to obtain higher current gain and lower power consumption. The electrical and optical properties of the epitaxial HPT structure were examined using capacitance-voltage (EC-V) measurements, photovoltage, photocurrent and micro-Raman spectroscopies. The current-voltage (dc I-V) characteristics as well as the results of time response measurements are also presented.