1. Low-frequency noise characteristics of self-aligned AlGaAs/GaAs HBTs with a noise corner frequency below 3 kHz
- Author
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Bumman Kim, Kim Ji-Young, Joon Woo Lee, Jin-Ho Shin, Kyu Hwan Ahn, and Yujin Chung
- Subjects
Materials science ,Passivation ,business.industry ,Infrasound ,Noise reduction ,Heterojunction bipolar transistor ,Optoelectronics ,Flicker noise ,business ,Current density ,Noise (radio) ,Cutoff frequency - Abstract
We have investigated the surface recombination and its 1/f noise properties of AlGaAs/GaAs HBT's as a function of the emitter-base structure and the surface passivation condition. It is found that the surface recombination 1/f noise can be significantly reduced by the heterojunction launcher of the abrupt junction with 30% Al mole fraction emitter. The depleted AlGaAs ledge surface passivation further suppresses the surface recombination currents. Consequently, we have achieved a very low 1/f noise corner frequency of 2.8 kHz at the collector current density of 10 kA/cm/sup 2/. The dominant noise source of the HBT is not a surface recombination current, but a bulk current noise. This is the lowest 1/f noise corner frequency among the III-V compound semiconductor devices, and comparable to those of low-noise Si BJTs.
- Published
- 2002
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