Turn-on phenomena in optically and electrically fired thyristors

An analytical solution of the time-dependent transport equation including surface recombination and optical injection for a diffused thyristor base is presented. By means of the classical two-transistor model, the turn-on transient may be predicted. Apart from the influence of technological parameters like base width, doping profile, and diffusion length, the effect of optical versus electrical injection as well as surface recombination are discussed. Surface recombination may significantly influence the optical turn-on threshold. Despite the rigorous simplicity of the model, the dynamic turn-on behavior of an optically fired high-voltage thyristor is in very good agreement with the experiment. The data, being presented for a wide range of parameters, are useful for practical design.     

光泵S_2蓝-绿激光

由于 500nm左右的蓝－绿光谱区恰是“水下窗口”因此积极地探索与发展高效率、低阈值、宽蓝－绿谱区可调僧激光器已成为目前研制新型激光器的重要课题之一。      

Schottky I/SUP 2/L

Schottky I/SUP 2/L uses the principles of integrated injection logic (I/SUP 2/L/MTL) and the properties of ion implantation to obtain improved performance at the same densities as conventional I/SUP 2/L. Schottky diodes are formed in the multicollectors of the switching transistor and reduce the signal swing, thus improving the power delay efficiency. An increase in the intrinsic speed limit is also feasible. The Schottky I/SUP 2/L structure and characteristics are described and contrasted with conventional I/SUP 2/L. A model which is useful for its design is discussed. Integrated test structures which provide direct comparison between conventional and Schottky I/SUP 2/L performance have been fabricated. The experimental results demonstrate a factor of 2 improvement in power-delay efficiency of Schottky I/SUP 2/L over conventional I/SUP 2/L.     

Schottky collector I/SUP 2/L

A new I/SUP 2/L gate which promises increased packing density and increased speed is discussed. It incorporates the use of a Schottky contact as the collector of the vertical switching transistor of an I/SUP 2/L gate. Calculations and experiments show that the problems associated with this structure (low downward beta) can be controlled by limiting both the fan-out and the fan-in. Delays of less than 10 ns have been measured using a 10-/spl mu/m technology and a 6-/spl mu/m-thick epi. A divide-by-two circuit with a maximum toggle frequency of 12.5 MHz has been built. The additional fan-in limitation of the logic is described.     

E2FAMOS—An electrically eraseable reprogrammable charge storage device

A new electrically eraseable nonvolatile charge storage device is described. The electrically eraseable floating-gate avalanche injection MOS (E²FAMOS) structure is an n-channel dual-stacked-gate MOS transistor programmed by avalanche injection from the pinchoff region and erased by hot electron injection from the floating gate.     

1/f noise in gate-controlled planar silicon diodes

Low-frequency excess noise in planar bipolar silicon devices was investigated by means of gate-controlled n+?p diodes. Within the range of parameter values covered in this investigation, it was found that the noise-power maxima invariably occur at gate bias voltages leading to depletion of majority carriers at the surface of the high-resistivity side of the p?n junction.     

Recent progress in the development of electrically and optically pumped dye vapor lasers

This paper reviews new results in the field of organic dye vapor lasers. Gain studies of the scintillator dye POPOP in liquid solution and in the vapor phase show that a dye vapor exhibits optical gain nearly as high as in the solution case under excitation by a N2laser. Superradiant emission has been observed from both, optically excited POPOP vapor and electron-beam excited vapor. The optimum operating conditions of an electron-beam pumped dye vapor-buffer gas system with high purity argon as buffer are reported. Potential energy transfer processes from the rare-gas buffer to the dye vapor are discussed. The metastable ionic species Ar+2has been identified as the most likely POPOP excitation source after intense electron pumping of the dense Ar buffer gas at typically 4-5 atm. An estimate of the conversion efficiency from electronic energy deposited in the Ar buffer to stimulated emission of the dye yields 5 percent. These results suggest that an efficient tunable electron beam pumped dye vapor laser is feasible.     

Determination of Si-SiO2 interface recombinationparameters using a gate-controlled point-junction diode underillumination

A novel method is presented to determine Si-SiO₂ interface recombination parameters. The device used is a polysilicon-oxide-semiconductor capacitor with a microscale central junction (a gate-controlled point-junction diode). Data analysis has been performed using a numerical scheme to find a quasi-exact solution for the current combining at the interface. It was found that the interface recombination parameters depend only weakly on trap energy in a wide range around midgap. The cross-section for capturing electrons was found to exceed the cross-section for capturing holes by a factor of 10² to 10³     

扩展的Schottky发射高分辨扫描电镜

本文从理论上评述了扫描电镜中作为电子源的五种发射制式，对冷场发射，热场发射，Ｓｃｈｏｔｔｋｙ发射和扩展的Ｓｃｈｏｔｔｋｙ发射四种制式，就虚源，能量分散，亮度，噪声等一些重要进行了详细的比较，指出了扩展的Ｓｃｈｏｔｔｋｙ发射的优越性。     

Characteristics of n-CuInSe2/Au Schottky diodes

The n-CuInSe₂/Au point-contact Schottky diode was studied using current-voltage and capacitance-voltage measurements. Various important physical parameters of these diodes were derived from both measurements, and these values are comparable with the results reported on planar Schottky diodes.     

An electrically pulsed HCl laser

A pulsed electrical discharge in a flowing mixture of Cl2and HI produces laser action on the 3 → 2 and 2 → 1 vibrational transitions of HCl.     

Far infrared optically pumped SO2laser

CO2laser pumping of the SO2molecule has produced far infrared (FIR) lasing on three rotational lines in the ν1excited state. Complete line assignments have been derived for all of the observed transitions.     

Frequency dividers by Schottky coupled I/SUP 2/L gates

A frequency dividing cell composed of four I/SUP 2/L gates and two Schottky diodes is proposed and analyzed. The cells are connected by one I/O line. n-p-n transistors need only two collectors. Simulation of the circuit with I/SUP 2/L gates of 3.2 ns/gate predicts the operating frequency up to 80 MHz. The operating frequency of 33 MHz was observed using a circuit built by discrete I/SUP 2/L gates with minimum propagation delay of 7.5 ns/gate and Schottky diodes.     

Improved Schottky clamped (T/SUP 2/L) circuits

Al-Si Schottky clamped transistors used as fast switching signal devices or in integrated circuits are superior to gold-doped transistors for such parameters as low-level current gain, leakage current I/SUB CO/, and propagation delay t/SUB pd/. A digital application is used to show how some of these parameters can be optimized for a T/SUP 2/L circuit, providing high switching speed (t/SUB pd/ 4 to 5 ns) and a 40-percent better worst-case low-level noise margin than the usual gold-doped T/SUP 2/L circuit.     

Al/TiSi_2/Si系统与肖特基势垒二极管的热稳定性

本文用x射线衍射及I—V测量法研究了Al/TiSi_2/Si系统热稳定性及肖特基势垒特性。热稳定性的研究结果表明;系统在550℃以下退火是热稳定的;在更高的温度下退火,Al开始与TiSi_2起反应,形成了(Ti_7Al_5)Si-(12)三元化合物。在进行电特性研究时,发现系统在450℃退火时,Al已渗透TiSi_2而使肖特基势垒二极管失效。     

Characteristics of LPCVD WSi2/n-Si Schottky contacts

Detailed current-voltage and capacitance-voltage characteristics of low-pressure chemical vapor deposited (LPCVD) WSi₂/n-Si Schottky contacts are reported in the temperature range of 21 to 170°C. The diode ideality factor n was found to decrease from a value of 1.46 to 1.15 as temperature was increased. Schottky barrier height φ_B, on the other hand, was found to increase from 0.72 to 0.86 V with temperature. These results suggest that diode characteristics are affected by surface and bulk effects, especially at lower temperatures. High-resolution transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy analyses revealed isolated regions of oxynitride at the silicide/silicon interface that are predominantly located where silicide grain boundaries intersect the silicon surface     

MoS2/MoTe2 Heterostructure Tunnel FETs Using Gated Schottky Contacts

2D transition metal dichalcogenide based van der Waals materials are promising candidates to realize tunnel field effect transistors (TFETs) with a steep subthreshold swing (SS) for low‐power applications. Their atomically flat, self‐passivated layers offer potentially defect free interlayer tunneling. There are still several issues that need to be addressed to experimentally achieve a steep SS, e.g., the Schottky contacts, impact of thick layers, and device architecture with respect to gate configuration. This paper resolves these challenges by experimentally demonstrating MoS₂/MoTe₂ TFETs and their electrical characteristics, in conjunction with ab initio simulations and surface Kelvin probe microscopy. The Schottky barrier's effect at the contact regions are isolated by fabricating individual buried gates below the contacts. Devices with different top and bottom gate configurations are produced to understand the impact of gate placement on the heterostructure characteristics. Quantum transport simulations are performed on MoS₂/MoTe₂ multilayer stack to evaluate the impact of multiple layers on TFET performance, effect of gate placement, and the mechanism behind indirect tunneling over the heterojunction region. This work highlights the influence of the Schottky contacts, multiple layers and the role of different gate configurations on the band‐to‐band tunneling phenomenon in 2D heterojunction TFETs.     

A low-barrier Schottky process using MoSi2

A technology to produce low-barrier MoSi2Schottky diodes for use in LSI bipolar circuits has been developed. Molybdenum disilicide is formed on single-crystal silicon by a self-aligned process under extremely clean conditions. Auger electron spectroscopy (AES) and infrared (IR) absorption techniques are used extensively to monitor the formation and thickness of MoSi2films. Capacitance-voltage and current-voltage measurements at varying temperatures are employed to characterize the Schottky barrier, which has a measured potential of 0.66 eV.     

C/V curves for gate-controlled diodes in silicon on sapphire

Experimental C/V curves are presented for gate-controlled diodes in silicon on sapphire and are analysed with a numerically implemented model, which shows the effects of a fixed layer of charge at the silicon-sapphire interface.     

Properties of high-energy electrically pulsed CO2lasers

The output properties of an electrically pulsed CO2laser have been investigated as a function of partial gas pressure and discharge voltage. The output pulse became sharper with increasing CO2pressure. The output pulse energy increased with increasing helium pressure up to a pressure where the output became independent of further increases. Output pulses of 24 joules at 3.6 MW and 3.6 percent efficiency were obtained at 1/10 atmosphere in a 3.5-meter-long 5-cm-bore laser tube.