Wideband analytical extraction technique of π‐equivalent circuit model for Si/SiGe heterojunction bipolar transistor in BICMOS process

Abstract

A developed analytical extraction technique of small‐signal π‐topology equivalent circuit model for Si/SiGe heterojunction bipolar transistor is presented. The intrinsic model parameters, including base resistance (Rb) which are difficult to extract in the previous works, are analytically extracted by utilising a novel set of exact equations that do not need any numerical fitting, special polarisation of the device or any kind of post processing. Moreover, the substrate effect and the distributed base‐collector junction are accurately modelled and extracted. To the authors knowledge, the extracted values using the presented methodology exhibit flattest and widest frequency independent behaviour among all those extracted with earlier published analytical techniques, especially for base resistance. Excellent agreement is noted between the S‐parameters measurements and their simulated counterpart using the extracted model in the frequency range from 40 MHz–40 GHz at different bias conditions.

Extraction of small‐signal model parameters of Si/SiGe heterojunction bipolar transistor using least squares support vector machines

“…The problem corners are the corners of the voltage region at which we want to extract SSECMPs. Base voltage (V B ) is chosen to vary from 0.8 to 0.9 V, while collector voltage (V C ) is varied between 1.0 and 2.0 V. The SSECMPs are extracted at these four corners using any traditional technique [2,3]. In this Letter, the procedure followed in [2] is adopted.…”

“…Base voltage (V B ) is chosen to vary from 0.8 to 0.9 V, while collector voltage (V C ) is varied between 1.0 and 2.0 V. The SSECMPs are extracted at these four corners using any traditional technique [2,3]. In this Letter, the procedure followed in [2] is adopted. The lowest and highest extracted values of each parameter are listed and considered the approximated boundary of each SSECMP.…”

“…All the aforementioned parameters are extracted using the presented methodology. However, beforehand, the bias‐independent emitter resistance ( R e ) is extracted as in [2].…”

“…In this Letter, the procedure followed in [2] is adopted. The lowest and highest extracted values of each parameter are listed and considered the approximated boundary of each SSECMP.…”

“…There are a lot of different techniques to extract SSECMPs. However, it can be categorised under two main conventional approaches, direct extraction, as an example [2], and optimisation‐based extraction, as an example [3]. In the former approach, a series of transformations from Z ‐parameters to Y ‐parameters and vice versa of the SSECM nested layers in conjunction with some sort of frequency analysis are needed to extract SSECMPs.…”