Characteristics of self-induced lightly-doped-drain polycrystallinesilicon thin film transistors with liquid-phase deposition SiO2 as gate-insulator and passivation-layer

As the passivation layer on the top of undoped offset region for offset-gate structured poly-Si TFTs is exposed to hydrogen plasma, a lightly-doped-like drain region could be equivalently self-induced. The hydrogenated polycrystalline silicon thin-film transistor of this structure, named self-induced lightly-doped-drain (SI-LDD) poly-Si TFTs, was first developed with liquid-phase deposition oxide as both the gate insulator and the passivation layer. This paper describes the optimum hydrogenation condition, and the electrical characteristics for the novel SI-LDD poly-Si TFTs. The effects of DC electrical stress on SI-LDD poly-Si TFTs are also described. Finally a model is proposed to explain the degradation phenomena observed in our SI-LDD devices     

Recessed-gate AlGaAs-InGaAs-GaAs pseudomorphic HEMT withSi-planar-doped etch stop layer

An improved slot etch technique based on an Si planar doped layer has been applied to gate recessing in the fabrication of AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistors (HEMTs). The devices exhibited comparable g_m with much better breakdown and leakage behaviour than conventional pseudomorphic HEMT devices     

Analysis of electromagnetic scattering from an anisotropic cylinderusing the FD-MEI method

The electromagnetic scattering from an anisotropic cylinder is analysed using the FD-MEI method. Some numerical results, which are in good agreement with the exact solutions when available, are given     

Epitaxial lift-off GaAs HEMT's

An extensive study of epitaxial lift-off (ELO) Al_0.3Ga _0.7As/GaAs modulation doped heterostructure high electron mobility field-effect transistors (HEMT's) is presented. Effects of ELO on electron transport properties of two-dimensional electron gas at AlGaAs/GaAs interface are investigated. An ELO HEMT with 1.5 μm gate length had a maximum extrinsic transconductance g_m-max=125 mS/mm, a unity current gain cut-off frequency f_t=10.5 GHz, and a maximum frequency of oscillation f_max=12 GHz. Statistical distributions of maximum intrinsic transconductance of ELO HEMT's are presented and compared with their on-wafer counterparts. Stability of the ELO HEMT's has also been evaluated by continuous operation at room temperature under dc bias     

单纵模激光的再生放大

调Ｑ激光器的输出单纵模脉冲经衰减和削波后，被注入到一Ｎｄ∶ＹＬＦ调Ｑ副腔里，注入脉冲能量１．２ｎＪ，放大以后的脉冲能量１．５ｍＪ，增益达１０６；脉宽由６ｎｓ压缩到４．５ｎｓ。实验和理论分析均表明，当注入信号脉宽短于放大器腔来回一周的时间时，副腔对单纵模激光的放大是一种再生放大行为，单纵模激光的再生放大消除了注入锁定中苛刻的腔长匹配要求。     

Amplified distributed reflective optical star couplers

A practical configuration for an amplified distributed reflective N-star coupler using 2×2 3-dB fiber couplers and minimum numbers of erbium-doped fibers, pump lasers, and standard fibers is presented. The constitution and characteristics of this coupler are investigated. Besides a tremendous amount of saving of the required standard fibers, this distributed coupler is more efficient, more reliable, more flexible for future expansion, and more cost-effective for application in optical networks     

Offset compensation scheme for analogue LMS adaptive FIR filters

Offset voltage in the adapting part of an analogue LMS adaptive filter, caused by clock feedthrough, causes serious degradation of the convergence and error performance of the filter. A compensation scheme for the clock-induced offset is described. Simulation results at both algorithmic and circuit level are presented.<>     

Stability of digital filters implemented with two's complementtruncation quantization

The stability of digital filters implemented with two's complement truncation quantization is investigated. Both the direct-form and normal-form realizations are considered and regions in the parameter plane are obtained where the filters are globally asymptotically stable. Regions within the stability triangle of a direct-form digital filter are also studied where limit cycles of period one and two are possible. The results are illustrated with several examples     

Threshold voltage and C-V characteristics of SOIMOSFET's related to Si film thickness variation on SIMOX wafers

C-V characteristics of fully depleted SOI MOSFETs have been studied using a technique for measuring silicon-film thickness using a MOSFET. The technique is based on C-V measurements between the gate and source/drain at two different back-gate voltages, and only a large-area transistor is required. Using this technique, SOI film thickness mapping was made on a finished SIMOX wafer and a thickness variation of ±150 Å was found. This thickness variation causes as much as a 100-mV variation in the device threshold voltage. The silicon-film thickness variation and threshold-voltage variation across a wafer shows a linear correlation dependence for a fully depleted device. C-V measurements of the back-gate device yield the buried-oxide thickness and parasitic capacitances. The effects of GIDL (gate-induced drain leakage) current on C-V characteristics are also discussed     

Analysis of nonlinear beam-wave interaction of gyro-peniotron at harmonics

An analysis of the nonlinear beam-wave interaction of the gyro-peniotron at high harmonic is presented in this paper. It bases on a ballistic large-signal theory of the gyropeniotron assuming a given RF field distribution in the resonator. The proposed method is applicable to arbitrary harmonic numbers and to arbitrary TE modes. Analytical results of its operational characteristics are given using computer simulations. E. g. an efficiency of 45% for the third harmonic has been calculated. The results show that the gyro-peniotron could be potentially a high efficiency, high power millimeter-wave device at a low magnetic field.