Noise properties of micro-wave heterojunction bipolar transistors

As the wireless communications of voice, video and data grows, the increasing demand of channels and bandwidth is driving the transceiver systems toward millimeter-wave frequencies. Noise performance of active devices represent a key issue of the electronic systems since at low frequencies 1/f noise and generation-recombination noise degrade the spectral,purity of the micro-wave oscillator while high frequencies noise can limit the performances of both the low-noise amplifier and the mixer. During past years heterojunction bipolar transistors (HBTs) have demonstrated attractive capabilities in terms of low-noise millimeter-wave performance. Many efforts were focused on the noise behavior versus material system, geometry device, bias and temperature in order to state, on the well suited technology for low-noise transceiver. In this paper, we propose to present a state of the art of noise properties of micro-wave HBT´s. Section II of the paper describes the low-frequency (LF) and high frequency (HF) noise characterization methods. Section III outlines a summary of previous works on excess noise and high frequency noise modeling in HBTs. Section IV addresses a brief description of the material used for HBT devices and their corresponding electrical performances. Section V and VI deal with the LF and HF noise properties of HBTs and finally, the conclusions are presented in section VII