High Frequency Noise Performance Research Articles

Improved noise analysis of distributed preamplifier with cascode FET cells

Improved noise analysis of a distributed amplifier (DA) with cascode unit cells is presented. The analysis is based on the lossy m-derived configuration, considering the effects of field-effect transistor resistances, as well as parasitic and intentional inductances, which have been ignored in previous research. Analytical expressions for the noise figure and equivalent input noise current density of the cascode DA are derived. The analysis also identifies the individual contributions from each noise source inside the cascode DA, providing insight into the noise of a DA. It is found from the analysis that the output noise current of cascode cell (~i/sub de//sup 2/) is the most significant contributor to the total noise of the DA over most of the operating frequency band. The gate termination noise (~i/sub Zg//sup 2/) has a large impact at the low-frequency end, while the input noise current of the cascode cell (~i/sub ge//sup 2/) degrades the high-frequency noise performance substantially. The resistive and inductive effects of the unit cells have been carefully studied by comparing the simulation results with those based on the lossless constant-k models, which shows that ignoring these effects may result in misleading results at high frequencies. To validate the noise analysis, the simulated noise figure of nine-section cascode DA monolithic microwave integrated circuit is compared with the measured data, yielding an excellent agreement over the entire operating frequency band.

Impact of Downscaling on High-Frequency Noise Performance of Bulk and SOI MOSFETs

Parameters limiting the improvement of high-frequency noise characteristics for deep-submicrometer MOSFETs with the downscaling process of the channel gate length are analyzed experimentally and analytically. It is demonstrated that the intrinsic Pucel's noise P, R, and C parameters are not strongly modified by the device scaling. The limitation of the noise performance versus the downscaling process is mainly related to the frequency performance (f/sub max/) of the device. It is demonstrated that for MOSFETs with optimized source, drain, and gate accesses, the degradation of the maximum oscillation frequency is mainly related to the increase of the parasitic feedback gate-to-drain capacitance and output conductance with the physical channel length reduction. Optimization of these internal parameters is needed to further improve the high-frequency noise performance of ultra deep-submicrometer MOSFETs.

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

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.

Improved microwave and noise performances of InGaP/In0.33Ga0.67As p-HEMT grown on patterned GaAs substrate

Microwave and noise performances of a highly strained InGaP/In0.33Ga0.67As pseudomorphic high electron mobility transistor (p-HEMT) grown on a patterned GaAs substrate and a conventional InGaP/In0.22Ga0.78As p-HEMT grown on a non-patterned GaAs substrate were compared. The highly strained InGaP/In0.33Ga0.67As p-HEMT grown on the patterned GaAs substrates showed substantial improvements in DC (drain saturation current and transconductance), microwave (fT and fmax), and low-frequency and high-frequency noise performances compared with those of the conventional InGaP/In0.22Ga0.78As p-HEMT grown on the non-patterned GaAs substrate.

An accurate and efficient high frequency noise simulation technique for deep submicron MOSFETs

Based on an active transmission line concept and two-dimensional (2-D) device simulations, an accurate and computationally efficient simulation technique for high frequency noise performance of MOSFETs is demonstrated. Using a Langevin stochastic source term model and small-signal equivalent circuit of the MOSFET, three intrinsic noise parameters (/spl gamma/, /spl delta/, and c) for the drain noise and induced gate noise are calculated. Validity and error analysis for the simulation are discussed by comparing the simulation results with theoretical results as well as measured data.

High-frequency noise performance of SiGe p-channel MODFETs

For the first time, an investigation into the microwave noise performance of SiGe-based MODFETs is presented. The devices were 0.1 µm gate-length p-channel MODFETs fabricated on a high-mobility SiGe strained-layer heterostructure grown by UHV-CVD and had a unity gain cutoff frequency fT of 42 GHz and maximum frequency of oscillation fmax of 69 GHz at a drain-to-source bias voltage Vds of –0.6 V. A minimum noise figure Fmin of 1.1 dB and an associated gain Ga of 18 dB were obtained at 3 GHz, while values of Fmin = 1.7 dB and Ga = 12 dB were obtained at 10 GHz. These values are comparable to those of SiGe production HBTs, and demonstrate the suitability of SiGe MODFETs for RF and microwave communications applications.

Microscopic noise modeling and macroscopic noise models: how good a connection? [FETs

Based on the active line concept, a novel approach for the calculation of the high frequency noise performance of field effect transistors (FET) is proposed. By using a simple analytical theory, the FET small signal equivalent circuit as well as the macroscopic noise sources and their correlation are calculated for different two-port terminations. Values of the usual dimensionless noise parameters P, R, C, gate noise temperature T/sub g/ and drain noise temperature T/sub d/ are then given and discussed. By comparison with a more realistic numerical modeling of the noise performance, the validity of the analytical noise model is discussed. The validity of Pospieszalski's noise model and its relations with Pucel's one is emphasized.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Influence of GaAs buffer thickness on low-frequency and microwave noise in GaAs MESFETs grown on InP substrates

The dependence on the GaAs buffer layer thickness of the low and high frequency noise performance of GaAs MESFETs grown on InP substrates has been investigated. The 1/f noise magnitude at f = 1 kHz and the minimum noise figure Fmin in the 2–12 GHz frequency range, measured for a buffer layer thickness varying from 1 to 5 μm, decreases when the buffer thickness increases. The results obtained for a buffer thickness of 3 μm or more are close to those observed on bulk GaAs and are consistent with the GaAs layer crystalline improvement observed by X-ray diffraction measurements.

Experimental evidence for trap-induced photoconductive kink in AlGaAs/GaAs HEMTs

The microwave small-signal and high frequency noise performance of AlGaAs/GaAs HEMTs have been assessed, both with and without illumination at room temperature. The measurements were carried out over the bias range where the photo-induced kink in the DC output characteristics is observed. The results obtained have been compared with our previously reported kink phenomenon in the output characteristics of these devices. The postulated electron trapping mechanism is confirmed as the cause of the kink

High-frequency FET noise performance: a new approach

A formulation is proposed for calculating the FET noise performance in the high-frequency range (EHF). In the first step, the concept of a local small-signal equivalent circuit is introduced, and a novel method for calculating the FET admittance parameters is proposed. In the second step, a novel formulation of the impedance field is given. It is shown that this approach reflects better the frequency evolution of the noise source values and consequently gives a better noise figure.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Modified Fukui model for high-frequency MESFETs

The letter will describe a modified form of the Fukui noise model to describe the high-frequency noise performance of MESFETs.

Effects of Radiation on the Noise Performance of Transistors

The predominant transistor noise sources are surveyed and related to both surface and bulk permanent damage radiation effects. The medium and high frequency noise performance of FET and bipolar transistors is not strongly affected by radiation until the devices themselves begin to fail. Low frequency 1/f noise is affected by relatively light radiation doses, but only with the junction FET can one make quantitative predictions of post-radiation noise performance. An additional noise source of very large amplitude is present while radiation induced photocurrent is being generated in transistors.