A new method for calculating the noise parameters of MESFET's and TEGFET's

Analytical formulas for the intrinsic noise sources of both MESFET's and TEGFET's are derived from a numerical noise modeling. Using these expressions the calculated noise figure is in good agreement with experimental findings. The influence of gd and Cgd on the noise figure is then pointed out and a comparison between the kf factor of MESFET's and TEGFET's is presented.     

GaAlAs红外发光二极管RTS噪声测试方法研究

针对GaAlAs红外发光二极管(IRLED) 随机电报信号(Random Telegraph Signal, RTS)噪声不易测量的特点,提出了一种自动温控RTS噪声测试新方法。通过分析GaAlAs IRLED的RTS噪声产生机理及特性,建立了GaAlAs IRLED的RTS噪声模型,对噪声测试的基本条件进行深入分析,并设计了自动温控测试系统。在10K的温度下对GaAlAs IRLED的RTS噪声进行测试,实验表明,该方法能准确的测量GaAlAs IRLED的RTS噪声,得到与噪声模型一致的结果,为GaAlAs IRLED可靠性的噪声表征提供了实验与理论依据。     

GaAlAs红外发光二极管低频噪声检测方法

通过分析GaAlAs红外发光二极管(IRED)的低频噪声产生机理及特性,建立了GaAlAs IRED的噪声模型,设计了一套低频噪声测试系统,通过该系统测量得到了GaAlAs IRED的低频噪声。实验表明,该方法能准确的测量GaAlAs IRED的低频噪声,发现其低频噪声主要表现为1/f噪声,得到与噪声模型一致的结果。该研究为GaAlAs IRLED可靠性的噪声表征提供了实验基础与理论依据。     

DC conduction and low-frequency noise characteristics ofGaAlAs/GaAs single heterojunction bipolar transistors at roomtemperature and low temperatures

The DC conduction and low-frequency noise characteristics of GaAlAs/GaAs single heterojunction bipolar transistors (HBTs) have been investigated at room temperature and at temperatures down to 5 K. The collector current dependence of the current gain was investigated at various temperatures. The low-frequency noise characteristics exhibit both 1/f and generation-recombination components. The noise characteristics are sensitive to changes in base current and insensitive to changes in collector-emitter voltage, thus suggesting that the noise source is located in the vicinity of the emitter-base heterojunction. The noise spectrum follows a simple model based on minority carrier trapping effects at the heterointerface     

电应力对GaAlAs红外发光二极管低频噪声的影响

在宽范围偏置条件下,测量了电应力前后GaAlAs红外发光二极管（IRED）的低频噪声,发现应力前后1／f噪声随偏置电流变化的规律没有改变,但应力后1／f噪声幅值比应力前增加大约i00倍。基于载流子数和迁移率涨落的理论分析表明,GaAlAs IRED的1／f噪声在小电流时反映体陷阱特征,大电流时反映激活区陷阱特征,1／f噪声的增加归因于电应力在器件有源区诱生的界面陷阱和表面陷阱,因而,1／f噪声可以用来探测电应力对该类器件有源区的潜在损伤。     

AC floating body effects in partially depleted floating body SOInMOS operated at elevated temperature: an analog circuitprospective

AC floating body effects in PD SOI nMOSFETs operated at high temperature are investigated. Both source/body and drain/body junction diode characteristics are greatly influenced by temperature, significantly impacting the ac kink effect as well its low-frequency (LF) noise characteristics. This is especially true for the pre-dc kink operation at high temperature. The increase of junction thermal generation current becomes an important body charging source and induces the LF Lorentzian-like excess noise     

Effect of Schottky barrier alteration on the low-frequency noise ofInP-based HEMTs

For the first time the effect of increasing the Schottky barrier's Al content of InP-based InAlAs-InGaAs HEMTs from 48 to 60% on the low-frequency (LF) drain and gate current noise is investigated. It is shown that the LF gate current noise S_IG(f) for the 60% case decreases by almost three decades, while the LF drain current noise S _IDS(f) stays at the same level. From small coherence values, it can be concluded that drain and gate noise sources can be treated separately which facilitates the LF noise modeling of these HEMTs     

Mode-hopping noise in index-guided semiconductor lasers and its reduction by saturable absorbers

Mode-hopping noise in index-guided semiconductor lasers is investigated. It is found that random switching between lasing modes and output power differences in those modes cause mode-hopping noise. An effective method to suppress such mode-hopping noise is proposed. High Te doping to an n-type GaAlAs cladding layer completely suppresses the noise. Te in GaAlAs forms a DX center that acts as a saturable absorber. This property stabilizes the laser mode and prevents mode competition. The minimum loss difference between lasing and nonlasing modes to suppress mode-hopping noise is also discussed.     

Double stage low-frequency noise equivalent circuit of green InGaN LEDs for description of noise characteristics

To explain the current dependences of the mean-square value of low-frequency (LF) noise current in green InGaN light emitting diodes (LEDs), a double stage low-frequency noise equivalent circuit of the LED is proposed. It is shown that the nonmonotonic dependence of the LF noise on the injection current in the LED can be explained by the effect of two LF noise generators: a noise current generator, which is localized near the heterojunction and is determined by tunnel-recombination processes at the interface, and a generator determined by recombination processes in the active region of the structure.     

Low-frequency noise in modern bipolar transistors: impact ofintrinsic transistor and parasitic series resistances

In modern submicrometer transistors, the influence of the internal base and emitter series resistances, on both the I-V characteristics and the LF noise at higher bias currents, becomes important. In this paper expressions are presented for the LF noise in transistors, where the influence of the series resistances has been taken into account. The expressions have been compared with recent experimental results from the literature obtained from modern submicrometer (heterojunction) bipolar transistors. At low forward currents the LF noise in such transistors is determined by spontaneous fluctuations in the base and collector currents. In most transistors at higher forward currents, the parasitic series resistances and their noise become important     

Comprehensive study on low-frequency noise characteristics insurface channel SOI CMOSFETs and device design optimization for RF ICs

Low-frequency (LF) noise, a key figure-of-merit to evaluate device technology for RF systems on a chip, is a significant obstacle for CMOS technology, especially for partially depleted (PD) silicon-on-insulator (SOI) CMOS due to the well-known kink-induced noise overshoot. While the dc kink effect can be suppressed by either using body contact technologies or shifting toward fully depleted (FD) operation, the noise overshoot phenomena still resides at high frequency for either FD SOI or poor body-tied (BT) SOI CMOSFETs. In this paper, floating body-induced excess noise in SOI CMOS technology is addressed, including the impact from floating body effect, pre-dc kink operation, and gate overdrive, followed by the proposal of a universal LF excess noise model. As the physical mechanism behind excess noise is identified, this paper concludes with the suggestion of a device design methodology to optimize LF noise in SOI CMOSFET technology     

The correlation between the low-frequency electrical noise of high-power quantum well lasers and devices surface non-radiative current

The low-frequency electrical noise, voltage–current (V–I) and electrical derivative characteristics of 980 nm InGaAsP/InGaAs/GaAlAs high power double quantum well (DQW) lasers are measured at different conditions. The correlation between the low-frequency electrical noise and surface non-radiative current of devices is discussed. The results indicate that the low-frequency electrical noise of 980 nm high power DQW lasers is mainly 1/f noise and has good relation with the devices surface current at low injection.     

Parasitic element influence on the wide-band electrical noise and modulation response of semiconductor lasers

The influence of parasitic elements on the wide-band electrical noise in GaAlAs BH-BOG lasers is investigated theoretically and experimentally. The results show that the maximum small-signal modulation bandwidth can be determined from measurements of the electrical noise spectrum. A small difference of the peak frequency in the optical intensity noise and the peak frequency in the electrical noise spectra is observed (about 200 MHz), and it is explained by introducing the nonlinear intrinsic diode impedance in the parasitic element model. However, the peak frequency in the small-signal modulation response spectrum coincides with the peak frequency in the electrical noise spectrum. It is also shown that the spectral line width, calculated from electrical noise measurements, is not significantly affected by the parasitic element filtering. The electrical noise level is observed to approach an inverse output power dependence at high pumping rates, in good agreement with theoretical calculations.     

Low-frequency noise in hot-carrier degraded nMOSFETs

This paper discusses the low-frequency (LF) noise in submicron nMOSFETs under controlled transistor aging by hot-carrier stress. Both traditional, steady-state LF noise as well as the LF noise under periodic large-signal excitation were found to increase upon device degradation, for both hydrogen passivated and deuterium passivated Si–SiO₂ interfaces. As hot-carrier degradation is slower in deuterium-annealed MOSFETs, so is the increase of the noise in these devices. The noise-suppressing effect of periodic OFF switching is gradually lost during hot-carrier degradation, as the LF noise under periodic large-signal excitation increases more rapidly than the LF noise in steady-state.     

Noise reduction in single longitudinal mode lasers by high-reflectivity coatings

Feedback-induced noise in single longitudinal mode semiconductor lasers was suppressed over a wide range of the amount of the optical feedback light by high-reflectivity facet coatings. A relative intensity noise value was as low as -143 dB/Hz at 3 mW output power under 1 percent of optical feedback in the GaAlAs lasers with high-reflectivity (0.75) facets.     

Electrical noise and RTS fluctuations in advanced CMOS devices

A brief overview of recent issues concerning the low frequency (LF) noise in modern CMOS devices is given. The approaches such as the carrier number and the Hooge mobility fluctuations used for the analysis of the noise sources are presented and illustrated through experimental results obtained on advanced CMOS generations. The use of the LF noise measurements as a characterization tool of large area MOS devices is also discussed. The main physical features of random telegraph signals (RTSs) observed in small area MOS transistors are reviewed. The impact of scaling on the LF noise and RTS fluctuations in CMOS silicon devices is also addressed. Experimental results obtained on 0.18 μm CMOS technologies are used to predicting the trends for the noise figure of foregoing CMOS technologies e.g. 0.1 μm and beyond. The formulation of the thermal noise underlying the LF fluctuations in MOSFETs is recalled for completeness.     

The kink-related excess low-frequency noise in silicon-on-insulatorMOST's

The phenomenology of the kink-related low-frequency (LF) noise overshoot in partially depleted (PD) silicon-on-insulator (SOI) MOS transistors is described in detail. The influence of various physical parameters is reported. Based on the observations, a comprehensive first-order theory for the feature is derived. The model is based on the charge fluctuations which are caused by deep-level assisted generation-recombination events in the depletion region of the transistor. It will be shown that the noise amplitude is proportional to the density of deep-level centers, while the peak position is a sensitive function of the saturation voltage. This follows from the postulated dependence of the capture time on the inverse substrate current. As will be shown, the standard expression for the multiplication current is in first order also valid for SOI MOST's, both at room temperature and at 77 K. Simulations demonstrate that the proposed model correctly predicts the dependence of the noise overshoot on the measurement frequency, on the gate voltage, the temperature and on the device length. Finally, the spectroscopic potential of the feature will be outlined and possible ways to render the technique truly quantitative are pointed out     

Ultralow dark current GaAlAs/GaAs MSM photodetector

An interdigitated GaAlAs/GaAs metal-semiconductor-metal photodetector designed to be fully integrable with HIGFET-based digital integrated circuits and which exhibit a dark current as low as 100 pA at 10 V bias voltage is presented. Static and dynamic responsivities are reported, as well as noise properties. Photocurrents (for bias voltage higher than 4 V) comparable to those measured with a pin photodiode, and a shot noise cutoff frequency in excess of 13 GHz were recorded.<>     

Analysis and modeling of low-frequency noise in resistive FET mixers

A complete analysis of the low-frequency (LF) noise is performed on resistive field-effect transistor (FET) mixers, where LF noise is created due to the self-mixing process of the local oscillator. First, a new scalable noise model for FETs in an ohmic channel bias regime (U/sub ds//spl ap/0 V) has been developed, which uses fluctuating resistances, instead of noise voltage or noise current sources. Measurements on a hybrid single-ended mixer prove a good accuracy of the proposed model and reveal a method to distinguish between the different noise sources. Further investigations discuss the LF noise in balanced mixers and explain the mechanisms of noise generation. All mixers under test operate in X-band (8, ..., 12 GHz) with IF below 1 MHz.     

基于低频噪声检测的光耦器件可靠性频域筛选新方法

针对光耦器件的可靠性筛选,本文提出全频段阈值筛选方法检测光耦器件内部低频噪声。根据光耦器件内部的低频噪声完成光耦器件可靠性的筛选。实验中利用光耦器件测试系统检测200只光耦器件内部的低频噪声,计算这200只光耦器件全频段平均噪声谱,确定筛选阈值,再根据光耦器件可靠性分类标准,判断被测器件可靠性等级。