Identification and modeling of 1/f noise in advanced bipolar technologies.

摘要

The 1/f noise in advanced bipolar transistors has been investigated. The transistors used in this work were poly-emitter bipolar transistors provided by Texas Instruments Inc. for its second generation BiCMOS technology, and Site heterojunction bipolar transistors provided by National Semiconductor Corporation for its first generation BiCMOS technology.; Both npn and pnp poly-emitter BJTs were tested for their noise performance. Two different experimental setups have been used to identify all possible noise sources. Measurements with variable bias resistance have been carried out in order to study the change in the relative contribution of each noise source. Transistors with different oxide thickness at the monosilicon and polysilicon emitter interface have been used for the noise analysis. Noise measurements on transistors with different size were used to identify the scaling effect on noise. The physical mechanism for each noise source has been explored in detail to understand how the noise properties differ in npn and pnp type devices with different emitter area size.; The effect of various design aspects on the noise characteristics of npn Site-base HBTs has been investigated. Transistors with collectors implanted selectively to retard the Kirk-effect have been tested. Devices with higher extrinsic base implant intended for smaller base resistance have been measured. The emitter-poly overlap length has been varied to investigate the effect of the encroachment of the extrinsic base into the emitter perimeter. In the non-selectively grown Site base layer, the proximity of the interface of the epitaxial and polycrystalline Site to the intrinsic base has been studied as well.