Fibrous carbon materials having a protective oxidation resistant coating

Conclusions -- A gas-phase method of depositing one- or multiple-component carbide coatings on CFM of various textile structures has been developed. With preservation of the strength and elastic characteristics of the CFM, the thermo-oxidative resistance of the material is increased, plus the temperature range for the decomposition is shifted into the higher temperature region — by 150–250°C as compared with the starting material.-- CFM with protective coatings are finding ever greater use in making filters for cleaning up high-temperature gas-air mixtures.VNIIPV. Translated from Khimicheskie Volokna, No. 3, pp. 47–48, May–June, 1991.     

Low dark current quasi-Schottky barrier MSM-photodiode structures on n-Ga/sub 0.47/In/sub 0.53/As with p/sup +/-Ga/sub 0.47/In/sub 0.53/As cap layer

The p/sup +/-cap layer was used to fabricate a metal-semiconductor-metal (MSM) interdigitated photodetector on Ga/sub 0.47/In/sub 0.53/As. The measured barrier height was Phi /sub Bn=/0.52 V, the ideality factor n=1.1 and average dark current density 2 mA/cm/sup 2/. A rise time of 45 ps at lambda =1.3 mu m under 2 V bias was measured for an MSM photodiode with 3 mu m finger width and finger gaps and an active area of 100*100 mu m/sup 2/.<>     

Effect of bipolar turn-on on the static current-voltagecharacteristics of scaled vertical power DMOSFET's

The parasitic bipolar transistor inherent in the power vertical Double Diffused MOSFET (DMOSFET) structure can have a significant impact on its performance and reliability. Selectively formed TiSi₂ films on source contacts were used to reduce the contact resistance to n ⁺ source diffusion. These devices exhibit “kinks” in the output I-V characteristics. High contact resistance of TiSi₂ to moderately doped p-body diffusion causes high output conductance. Detailed two-dimensional numerical simulations are used to investigate the effect of the parasitic bipolar transistor on the static characteristics of scaled silicided DMOSFET's. The high contact resistance of TiSi₂-p-body interface leads to a floating potential and causes significant reduction in the MOS gate threshold voltage and results in a premature bipolar turn-on. It is shown that the parasitic bipolar turn-on places an important constraint on the scalability of the device into the submicron regime. A novel self-aligned DMOSFET structure with a shallow diffused p⁺ region is shown to eliminate this effect. Numerical simulations are shown to be in excellent agreement with the measured data at various temperatures     

Measurement of the Hardness of Thin Films

A method for evaluating the hardness of coatings with nanosize thickness is suggested. The method includes the determination of the hardness of the “coating-substrate” composition by indenting the coating and subsequent computation of the hardness with the use of the additivity rule. This requires determination of the thickness of the coating, of the hardness of the substrate, and of the indentation depth.     

Fast frequency estimation and tracking using Lagrange interpolation

A computationally efficient and accurate frequency estimation and tracking algorithm is proposed, based on the adaptive frequency estimator (AFE) of Etter and Hush. A Lagrange interpolator (a fractional delay filter) is used to estimate the gradient of the performance surface of the adaptation, which enables highly accurate estimation. The performance of the new algorithm is demonstrated in the context of tracking a chirp signal in noise     

GaN材料系列的研究进展

ＧａＮ及其合金作为第三代半导体材料具有一系列优异的物理和化学性质，在光电子器件，高温大功率电子器件及高频微波器件应用方面具有广阔的前景，已成为当前高科技领域的研究重点，论述了这种材料的研究历史与发展现状，物理与化学性质，薄膜的生长方法及在光学电子和微电子器件应用于方面的研究进展。