Analytical Determination of MOSFET's High-Frequency Noise Parameters From NF$_{50}$ Measurements and Its Application in RFIC Design

This paper presents detailed results from modelling the four noise parameters: minimum noise figure (NFMIN), noise resistance (RN), optimal source resistance (RS,OPT), and reactance (XS,OPT) as functions of frequency and collector-biasing current. Compared to previous BJT (bipolar junction transistor) high-frequency noise models, we include the emitter resistance, which results in an increased input device impedance, and a degeneration of the device transconductance. We also give an explicit formula for the noise resistance. We present noise results for polysilicon emitter bipolar transistors as a function of emitter areas to demonstrate how the noise parameters scale with emitter areas over a range of frequencies. However, these results are given only for devices in which the pad impedances are much larger than the device input impedance, so that very little input signal is lost through the pads to ground.

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Optimizing SiGe HBTs technology using small-signal and high frequency noise device's modeling

MRS Proceedings ◽

10.1557/proc-809-b6.2 ◽

2004 ◽

Vol 809 ◽

Author(s):

J.G Tartarin ◽

G. Cibiel ◽

A. Monroy ◽

V. Le Goascoz ◽

J. Graffeuil

Keyword(s):

Technological Process ◽

High Frequency ◽

Low Noise ◽

Rapid Expansion ◽

Base Layer ◽

Frequency Noise ◽

Small Signal ◽

Technological Parameters ◽

High Frequency Noise ◽

Noise Parameters

ABSTRACTThe rapid expansion of SiGe technologies during the last decade essentially due to civil telecommunication's applications have led Si/SiGe based heterojunction bipolar transistors (HBTs) to excellent performance levels, allowing high frequency low noise circuit designs such as linear low noise amplifiers( RF noise) or also low-phase noise oscillators (LF noise). Among these technologies, the SiGe BiCMOS one integrates digital and RF functions on the same chip. Fast improvements of the technological process have been performed thanks to large efforts allowed to characterization and modeling of the devices. We have investigated on the influence of technological parameters such as Germanium profile, doping level and thickness of the base layer (5 different wafers) on the dynamic and high frequency noise performances to converge towards the optimum technological process (now available with the BiCMOS6G processed by ST microelectronics). We made use of scattering parameters [S] measurements on the devices to extract the electrical parameters of our small signal model. The high frequency noise parameters based on the electrical model (with noise sources added to the junction, resistances) are simulated and compared with the measured noise parameters of the devices. The four noise parameters (Fmin, Rn, and complex Γopt) measurements have been performed from 1 GHz to 12 GHz, and the dynamic S parameters measurements have been realized in the 40 MHz-40 GHz range. These models have been used to enable the identification of the limiting parameters on the dynamic performances and on the high frequency noise parameters.

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