论文标题:GaAs MESFET器件与光通信GaAs电路的研究
Research of Automobile Engine Performance Test and Fault Diagnosis Expert System
论文作者 詹琰
论文导师 夏冠群,论文学位 博士,论文专业 微电子学与固体电子学
论文单位 中国科学院上海冶金研究所,点击次数 656,论文页数 108页File Size4376k
2001-05-01论文网 http://www.lw23.com/lunwen_138402/ GaAs;MESFET;阈值电压均匀性;旁栅效应;光纤通信;判决电路;时钟提取电路
GaAs;MESFET;threshold voltage;sidegating effect;fiber optic communication;decision circuit;clock recovery circuit
GaAs器件与电路具有高速度、低功耗、小噪声、耐高温、抗辐射等优点，在光纤通信、卫星、超高速计算机、高速测试仪器、移动通讯和航空航天等领域中有着重要的应用。而近年来，光纤通信技术的迅速发展使得超高速GaAs集成电路的研究成为必然。随着GaAs集成电路的发展，集成度的提高，对GaAs单晶阈值电压均匀性的要求也越来越高。 本文讨论了GaAs MESFET器件模型。由二区间模型导出了I_(DS)与V_(GS)和V_(DS)的关系。但由于计算过于复杂，而工艺又多变，使用物理模型处理电路模拟时，误差较大。因此在电路模拟程序SPICE或PSPICE中通常采用Curtice模型和Statz模型。研究结果表明使用Sta地模型更适合GaAs电路的模拟。 本文设计了一套适合多种工艺的阈值电压均匀性研究测试版图，包括多种材料参数及工艺参数测试图形。分别对采用隔离注入挖槽工艺和平面选择离子注入自隔离工艺制备的GaAs MESFET阈值电压均匀性进行了比较研究。结果表明，采用平面工艺制备的GaAs MESFET阈值电压均匀性比采用挖槽工艺制备的GaAs MESFET阈值电压均匀性更好。 本文对分别采用隔离注入挖槽、平面自隔离和平面离子注入隔离三种工艺制备的GaAs MESFET旁栅效应进行了研究。结果表明，采用注入隔离工艺制备的MESFET的旁栅效应比采用自隔离工艺制备的MESFET的旁栅效应要小。因此，采用注入隔离工艺可以减小器件的旁栅效应。另外，还采用平面选择离子注入隔离工艺，开展了旁栅效应的光敏特性、迟滞现象、旁栅效应对MESFET阈值电压的影响、MESFET漏源电压对旁栅阈值电压的影响、漏源交换对旁栅阈值电压的影响、旁栅阈值电压与旁栅距的关系、旁栅效应与浮栅的关系等研究。 本文建立了一套阈值电压自动测试系统，可对半绝缘GaAs单晶上制作的 MESFET器件的阈值电压进行自动测量，具有效率高、可靠性好的优点。测 试样品可以为rpZ和p3英寸以及p3英寸以下不规则片，并可给出阈值电压的 测量数据，作出阈值电压的mapping图，对阈值电压进行统计，计算阈值电 压的统计平均值、标准偏差等。该系统既是国内第一套也是国内独有的一套 GaAs阈值电压自动测试系统，对于开展国产GaAs材料与阈值电压均匀性关 系的研究具有重要的意义。 本文开展了2．SGb乃光纤通信用GaAS超高速判决电路的研究，设计了栅 长…m、耗尽型GaAs MESFET判决电路，经过PSPICE电路模拟和实际流片；测试，均验证该电路功能正确，达到了设计要求。电路判决灵敏度为20mV，5 静态功耗为 35mw，芯片面积为 0．76 minXI．08mm，传输速率可达 2．SGb儿， 可应用于覆盖二．SGb／S系列光纤通信系统。该研究在国内属先进水平。 本文进行了2．SGb沾光纤通信用GaAs超高速时钟提取电路的研究，设计 的时钟提取电路经SPICE模拟，结果表明，电路可实现正确的功能，时钟频。率达 2．5 GHz。在国内还未见这方面的研究报道。由于实验条件和时间的限制， 未对该电路进行流片工作。
GaAs devices and circuits have some distinct advantages such as high speed, low power dissipation, low noise, wide operation temperature and high radiation hardness. The applications of GaAs include fiber optic communication, satellite communication, super high speed computer, high speed test instrument, mobile communication, etc. In recent years, the development of fiber optic communication has been the driving force of GaAs IC抯 growth. With the increase of the integration of GaAs IC, the research of the threshold voltage uniformity is becoming more and more important. The models of GaAs MESFET have been discussed. The drain current-voltage relations have been derived from two region model. But the complex calculation and the changing process make the physical model be unsuitable for circuit simulation. So the Curtice model and the Statz model in SPICE or PSPICE circuit simulation program is most widely used for GaAs IC design. It is found that the Statz model is better. A test structure for measurement of the threshold voltage uniformity has been designed. In order to get the influence of different process on the threshold voltage uniformity, GaAs MESFETs are fabricated in recessed-gate process and planer selectively implanted process. The results show that the threshold voltage uniformity using planer selectively implanted process is better. The influence of different process on sidegating effect of GaAs MESFET has been studied using recessed-gate process, planer selectively implanted process and planar boron implanted process. The results show that the sidegating threshold voltage is higher when adjacent devices are isolated by boron implantation, which means that boron implantation significantly improves the electrical isolation between devices and reduces the sidegating effect. We also studied some characteristics of sidegating effect using planar boron implanted process including photosensive, hysteresis, influence of sidegating effect on MESFET threshold voltage, influence of drain-source voltage on sidegating threshold voltage, influence of exchanging drain and source electrode on sidegating threshold voltage, relation between sidegating threshold voltage and the distance of side-gate and MESFET, relation between sidegating effect and floating gate, and so on. A threshold voltage auto-test system has been set up which can automatically get the threshold voltage of MESFET on semi-insulating GaAs crystal. The test sample may be D2 inch, D3 inch, or other size less than cD3 inch. Useful results can be gotten from this system such as data of threshold voltage, the mapping of threshold voltage, statistic average value and standard deviation of threshold voltage, etc. This system is the frist and the only GaAs threshold voltage auto-test system of the nation and it is significant for promoting the research of the relation between threshhold voltage uniformity and GaAs materials made in our country. A super high-speed GaAs decision circuit applied to 2.5Gb/s fiber optic communication has been designed. The monolithic GaAs decision circuit with 1~.tm depletion-mode GaAs MESFET抯 is fabricated. It is proved by PSPICE circuit simulation and test that the circuit can deal with input signal rightly and produce correct digital output signal. The circuit can operate at 2.8Gb/s, so it can be applied to 2.5Gb/s fiber optic communication. A super high-speed GaAs clock recovery circuit applied to 2.5Gb/s fiber optic communica
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