电力静电感应晶体管大电压特性的改善

A novel structure for designing and fabricating a power static induction transistor（SIT）with excellent high breakdown voltage performance is presented.The active region of the device is designed to be surrounded by a deep trench to cut off the various probable parasitical effects that may degrade the device performance,and to avoid the parallel-current effect in particular.Three ring-shape junctions（RSJ）are arranged around the gate junction to reduce the electric field intensity.It is important to achieve maximum gate–source breakdown voltage BVGS, gate–drain breakdown voltage BVGD and blocking voltage for high power application.A number of technological methods to increase BVGD and BVGS are presented.The BVGS of the power SIT has been increased to 110 V from a previous value of 50–60 V,and the performance of the power SIT has been greatly improved.The optimal distance between two adjacent ring-shape junctions and the trench depth for the maximum BVGS of the structure are also presented.     

APPLICATION OF FREQUENCY DOMAIN TECHNIQUE IN HLS

The paper introduce the measurement of some beam parameters for Hefei Light Source(HLS)by frequency domain technique ,which include the betatron tune, average beta function ,natural chromaticity,corrected chromaticity ,and center frequency.Additionally ,the measurement of the influence of DC clearing electrodes on the betatron tune shift is also described.Some measurement results are given .The measurement results are compared with the theoretical values and shoen to be in good agreement.     

Development of an S-band klystron with bandwidth of 11%

This letter introduces the design ideas, simulation and test results of an S-band klystron with bandwidth of 11%, which was developed by the Institute of Electronics, Chinese Academy of Sciences (IECAS).On the peak power level of 800 kW, the efficiency of klystron is more than 30%; the gain is more than 41 dB; the equal-driving relative instantaneous bandwidth is over 11%; the average power is larger than 8kW, and the power fluctuation within bandwidth is less than 1o5 dB.     

IRRADIATION DAMAGES IN ELECTRON BEAM LITHOGRAPHY

The irradiation damages in the electron beam lithography(EBL)to Al-gate MOS capacitors inthe ranges of 10—30keV and 10~(-6)—10~(-3)C·cm~(-2) and the effects of annealing on damages at lowtemperature(<500℃)are given.The research on damages caused by high electron energy(30keV)and ultra-high dosages(10~(-4)—10~(-3) C·cm~(-2))is important and useful to the EBL.The resolution canbe improved by high electron energy.Both the EBL with vapor-development and withoutdevelopment are all operated at ultra-high dosages.After irradiations,the concentrations of inter-face states can increase by about one to two orders of magnitude and the flat-band voltages by abouta few to more than ten volts.Under constant exposure dosages,the fiat-band voltages areindependent of the changes of electron energies in certain energy ranges.Under constant electronenergies the concentrations of interface states are independent of the changes of exposure dosages incertain dosage ranges.After annealing,the flat-band voltages can recover the values before theirradiations for energies and dosages in the ranges of 10—30keV and 1×10~(-6)—6×10~(-3)C·cm~(-2)respectively.The interface state concentrations due to the damages of ultra dosages can not beremoved completely.     

Analysis and design of CW-LD pumped stable Q-switched laser

A high power continuous wave (CW) laser diode (LD) pumped acousto-optic Q-switched Nd:YVO4 laser is presented. A short pulse at the 1064 nm is obtained. With a repetition rate of 50 kHz, the maximum average output power of 5.72 W is achieved. The optical conversion efficiency and the slope efficiency are up to 28% and 32.4% respectively. At the repetition rate of 10 kHz and the pulse width of 16.3ns, the maximum single pulse energy of 286 μJ and the peak power of 13kW are acquired. The laser can be used as a signal source in the free-space optical communication. The output signal agrees with the modulate signal well.     

Development of 50MW S-band klystron

This letter reports the development of a 50MW S-band klystron in the Institute of Electronics, Chinese Academy of Sciences （IECAS）. It adopted a structure of six-cavity and single output window. Under conditions of an RF （Radio Frequency） pulse width of 4t, ts, a beam voltage of 305,9kV and a beam current of 368A, the peak output power has achieved 51.4MW with an efficiency of 45.6% and a gain of 54dB.     

一种采用多个渐变反型电荷层优化电场的LDMOST

A lateral double-diffused metal-oxide-semiconductor field effect transistor （LDMOST） with multiple n-regions in the p-substrate is investigated in detail. Because of the decrescent n-regions, the electric field distribu- tion is higher and more uniform, and the breakdown voltage of the new structure is increased by 95%, in comparison with that of a conventional counterpart without substrate n-regions. Based on the trade-off between the breakdown voltage and the on-resistance, the optimal number of n-regions and the other key parameters are achieved. Furthermore, sensitivity research shows that the breakdown voltage is relatively sensitive to the drift region doping and the n-regions＇ lengths.     

980nm垂直腔面发射激光器线阵及其温度特性研究

A 980 nm bottom-emitting vertical-cavity surface-emitting laser linear array with high power density and a good beam property of Gaussian far-field distribution is reported. This array is composed of five linearly arranged elements with a 200 μm diameter one at the center, the other two 150μm and 100μm diameter ones at both sides of the center with center to center spacing of 300μm and 250μm, respectively. A power of 880 mW at a current of 4 A and a corresponding power density of up to 1 kW/cm^2 is obtained. The temperature dependent characteristics of the linear array are investigated. The thermal interaction between the individual elements of the VCSEL linear array is smaller due to its optimized element size and device spacing, which make it more suitable for high power applications. A peak power of over 20 W has been achieved in pulsed operation with a 60 ns pulse length and a repetition frequency of 1 kHz.     

Q-switched and Mode-locked Characteristics of Cr^4＋： YAG Crystal

The passively Q-switched and mode-locked （QML） characteristics in a diode-pumped Nd： GdVO4 laser with Cr^4＋： YAG saturable absorbers have been demonstrated. A maximum average output power of 710 mW has been obtained in the QML laser. The maximum energy of a single Q-switched pulse is 52.5μJ, with the corresponding pulse width of 30 ns and the peak power of 1.75 kW, at the incident pump power of 7. 75 W. The repetition rates of the Q-switched envelope and the mode-locked laser pulse are 16.7 kHz and 680 MHz, respectively.     

Q-switched and Mode-locked Characteristics of Cr~(4+)∶YAG Crystal

The passively Q-switched and mode-locked(QML) characteristics in a diode-pumped Nd∶GdVO_4 laser with Cr~(4+)∶YAG saturable absorbers have been demonstrated. A maximum average output power of 710mW has been obtained in the QML laser. The maximum energy of a single Q-switched pulse is 52.5μJ, with the corresponding pulse width of 30ns and the peak power of 1.75kW, at the incident pump power of 7.75W. The repetition rates of the Q-switched envelope and the mode-locked laser pulse are 16.7kHz and 680MHz, respectively.     

S波段多注宽带速调管的研制

本文介绍了S波段200kW多注宽带速调管的研究工作。给出了多注速调管及其电子光学和聚焦系统、宽带输出电路的设计和计算结果。并给出了我国第一批实验型多注宽带速调管的性能:工作电压19kV时,控制极负偏压为7kV,脉冲电流32.25A,导流系数12.3P,电子注直流通过率91.8％。最大输出功率252kW,平均功率3.5kW,效率41％,增益49dB,带宽9.1％,带内功率波动1.7dB。     

宽脉冲大功率多注速调管

介绍了近期研制的X波段宽脉冲大功率栅控多注速调管的情况,该多注速调管在1.1ms脉冲宽度下实现了130MHz内6kW平均功率的稳定指标。本文对其结构特点也作了相应的介绍。     

中功率宽带多注速调管的研制进展

介绍了Ku波段中功率宽带多注速调管的最新研制进展情况,该管实现了工作电压14 kV、带宽大于1.8%、脉冲功率大于20 kW的指标。文中给出该管的试验数据,并对其中的关键技术进行了分析。     

Demonstration of an S-band, 600-kW fundamental-mode multiple-beam klystron

We present initial experimental results from the successful operation of a 600-kW peak, fundamental-mode multiple-beam klystron (MBK). The eight-beam device operates at a cathode voltage of /spl sim/45 kV and a total beam current of /spl sim/32 A with an axial guiding magnetic field of 1.8-2.2 kG. In the absence of radio-frequency (RF) drive, the measured beam transmission is in excess of 99%; at a driven frequency of 3.25 GHz, the measured beam transmission at saturation is /spl ges/97%, where the four-cavity circuit generates a peak power of /spl sim/600 kW with an electronic efficiency of 40%. The measured beam transport and RF performance are in excellent agreement with predictions made by the three-dimensional gun/collector code, MICHELLE, and the large-signal klystron code, TESLA. The accuracy of the design codes enabled the achievement of a working device in a single hardware design pass.     

X波段同轴腔多注速调管的研究

开展了具有同轴谐振腔互作用电路和双模工作杆控电子枪的X波段同轴腔双模多注速调管的研究工作.结合数值计算和冷测实验,对工作于TM₃₁₀高次模的同轴谐振腔模式分布和特性参数进行研究,获得了可满足多注速调管要求的谐振腔特性阻抗和良好的模式稳定性.采用具有双控制极的新型杆控多注电子枪及电子光学系统,可使多注速调管具有双模的新工作特性,通过数值模拟获得了优化的几何参数和具有良好层流性和波动性的空心多电子注.对采用6个电子注和5个谐振腔的X波段多注速调管进行了注波互作用大信号计算,结果表明当电子注电压为21.5kV,脉冲电流为14.4A时,可在30MHz频带范围内获得的100kW左右的脉冲输出功率,互作用效率大于30%,增益大于36dB.     

相对带宽大于8%的C波段宽带多注速调管

本文介绍中国科学院电子学研究所研制成功的相对带宽8%的C波段宽带多注速调管。C波段宽带多注速调管KC4137和KC4148在100 kW和160 kW功率电平上,获得了相对带宽8.1%和8.5%,相应的最低效率为29%和32.5%,平均功率为5 kW和8 kW。论文分析了由双间隙输出腔引起的杂谱（寄生输出）,讨论了抑制杂谱的方法。     

Experimental Study and Analysis of an S-Band Multiple-Beam Klystron With 6% Bandwidth

We present experimental results and analyses of an eight-beam five-cavity multiple-beam klystron (MBK) operating at a center frequency of ~3.2 GHz. The device met its performance goals in its first hardware implementation, generating a peak RF output power of 600 kW and a 3-dB bandwidth of ~6%. The circuit was modeled with TESLA, a 2.5-D large-signal klystron/MBK code that was extended to enable simulations of the low- Q multiple-gap cavities used to increase the bandwidth. Details of the model and underlying theory are described, and the simulation results are compared with experimental measurements. The good agreement between the model and the experiment provides a validation for our tools and techniques that will be used in the design of future devices.     

The multiple-beam klystron

The multiple-beam klystron (MBK) is a device for extending klystron power generation capability at a given frequency by a factor of ten or more. The MBK utilizes a multiplicity of electron beams in conjunction with multiwavelength waveguide circuits. These circuits are periodically loaded and operate in thepi/2-mode. The efficiency, bandwidth, gain and stability of the MBK are equal to or better than that of the single-beam prototype klystron. Furthermore, the MBK permits generation of a given power level at an unusually low voltage, thus minimizing insulation, X-radiation, and modulator problems. An MBK utilizing ten external-circuit klystrons has been built for 750-Mc operation to demonstrate the principle of the device. A single main magnetic circuit is used to focus all beams simultaneously. An RF power output ten times that of one klystron was measured, corresponding to an efficiency of 44 per cent. Bandwidth and gain were identical with single-beam prototype operation. Individual beam drop-out tests were made which showed no disruption of operation in case of the failure of one or more beams. Limited tests tend to confirm the conclusion that the harmonic content of an MBK can be lower than that of a single-beam klystron.