Title :
High-gain resonant InGaAlAs/InGaAs heterojunction bipolar phototransistors grown by molecular beam epitaxy
Author :
Dodabalapur, Ananth ; Chang, T.Y.
Author_Institution :
AT&T Bell Lab., Holmdel, NJ
fDate :
12/1/1991 12:00:00 AM
Abstract :
Summary form only given. Results obtained with two approaches that significantly enhance the gain and sensitivity of InP-based heterojunction phototransistors (HPTs) grown by molecular beam epitaxy (MBE) are described. The use of quaternary InGaAlAs (300 K, E g~1.08 eV) as the high-bandgap emitter layer improves the quality of the emitter-base interface and leads to high current gains, even at very low current levels. For heterojunction bipolar transistors (HBTs) with a circular (50-μm diameter) emitter, DC current gains of more than 9000 were obtained at a current density of 1000 A/cm2 . In the second approach to enhancing the gain and sensitivity of HPTs while keeping the absorbing layer thickness the same, a resonant structure in which the active layers are part of a Fabry-Perot cavity with the end reflectors being gold (which also serves as the emitter contact) and an InAlAs/InGaAlAs quarter-wave stack was designed
Keywords :
III-V semiconductors; aluminium compounds; cavity resonators; gallium arsenide; heterojunction bipolar transistors; indium compounds; molecular beam epitaxial growth; phototransistors; Au end-reflectors; DC current gains; Fabry-Perot cavity; HBT; HPT; InGaAlAs-InGaAs-InP; MBE; absorbing layer thickness; active layers; emitter-base interface; heterojunction bipolar phototransistors; high-bandgap emitter layer; molecular beam epitaxy; quarter-wave stack; resonant structure; Capacitance; Doping; Heterojunctions; Indium gallium arsenide; Jacobian matrices; Molecular beam epitaxial growth; Phototransistors; Poisson equations; Resonance; Robustness;
Journal_Title :
Electron Devices, IEEE Transactions on