某型低接触电阻率异面GaAs半导体光导开关的研究
发布时间：2019-02-23 10:14
【摘要】：光导开关(Photoconductive semiconductor switch, PCSS)也就是通过光控制导通与关断的半导体材料开关。光导开关是一种利用光能量激励半导体材料,使其电导率发生变化而产生电脉冲的光电转换器件。光导开关具有功率密度高(MW量级)、响应速度快(ps量级)、触发抖动低(ps量级)、抗电磁干扰能力强(良好的光电隔离)、体积小、易集成的优点。在大电流点火装置、拒止武器和高功率微波系统、精密时间同步、THz技术、瞬态测试、冲激雷达、电磁干扰与攻击系统等领域应用广泛。光导开关诞生以后,研究人员就孜孜不倦的研究着不同用途的光导开关的体材料,对于材料的实验和研究从未停止。第一代半导体材料中的Si,第二代半导体材料中的GaAs,第三代半导体材料中的SiC都被广泛应用到光导开关中。常温下GaAs的电子迁移率可达8500cm2/V·s,比Si和SiC都要高得多,载流子的寿命为O.1ns到10ns,实验数据表明,对于特定波长的光激励,GaAs光导开关的电压转换有着更高的效率。光导开关的核心部分是重掺杂半导体有源区与多层金属经合金化形成电极的欧姆接触。电极接触电阻的大小直接决定了光导开关的开关速度、效率和增益等性能,因此准确的测量光导开关欧姆接触的参数是研究光导开关的先决条件。欧姆接触性能的表征可以通过Ⅰ-Ⅴ特性曲线和接触电阻率测量来体现,也可以通过显微镜来扫描其形貌特征来直观表现。一个器件要想获得良好的性能,必须尽可能的降低器件电极的接触电阻率,从而减小接触上的压降,增大器件工作部分的压降。本论文的研究工作是围绕GaAs光导开关的制作工艺和欧姆接触性能分析研究展开的。论文叙述了光导开关的研究意义、结构和应用,在此基础上,介绍了光导开关的原理和欧姆接触的原理；通过对比和项目的要求确定了光导开关的衬底材料、电极金属体系和光导开关的结构；介绍了常见的欧姆接触电阻率测量的方法和光导开关的制作工艺;用圆点传输线测量方法对样品的接触电阻率进行了测量,用半导体电学特性测试仪测量了欧姆接触的I-V特性曲线,并且用AFM原子扫描显微镜对金属电极的形貌进行了扫描；论文最后对研究工作进行了总结和展望。
[Abstract]:The photoconductive switch (Photoconductive semiconductor switch, PCSS) is a semiconductor material switch that is controlled by light to switch on and off. Photoconductive switch is a kind of optoelectronic conversion device which uses light energy to excite semiconductor material and make its conductivity change and produce electric pulse. The photoconductive switch has the advantages of high power density (MW order of magnitude), fast response speed (ps order of magnitude), low trigger jitter (ps order of magnitude), strong anti-electromagnetic interference ability (good photoelectric isolation), small size and easy integration. It is widely used in many fields, such as high current igniting device, withholding weapon and high power microwave system, precision time synchronization, THz technology, transient test, impulse radar, electromagnetic interference and attack system, etc. Since the birth of photoconductive switches, researchers have been working tirelessly to study the bulk materials of photoconductive switches for different purposes, and the experiments and research on materials have never stopped. Si, in the first generation semiconductor materials, GaAs, in the second generation semiconductor materials, SiC in the third generation semiconductor materials are widely used in photoconductive switches. The electron mobility of GaAs can reach 8500cm2/V s at room temperature, which is much higher than that of Si and SiC. The lifetime of carrier is from O.1ns to 10ns. The experimental data show that the voltage conversion of GaAs photoconductive switch is more efficient than that of Si and SiC. The core part of the photoconductive switch is the ohmic contact between the heavily doped semiconductor active region and the multilayer metal by alloying. The contact resistance of the electrode directly determines the switching speed, efficiency and gain of the photoconductive switch. Therefore, accurate measurement of the parameters of the ohmic contact of the photoconductive switch is a prerequisite for the study of the photoconductive switch. The ohmic contact properties can be characterized by I-V characteristic curve and contact resistivity measurement, or by scanning the morphology of ohmic contact through microscope. In order to obtain good performance, a device must reduce the contact resistivity of the device electrode as much as possible, so as to reduce the pressure drop on the contact and increase the pressure drop in the working part of the device. The research work of this thesis is focused on the fabrication process of GaAs photoconductive switch and the analysis of ohmic contact performance. The research significance, structure and application of photoconductive switch are described in this paper. On this basis, the principle of photoconductive switch and the principle of ohmic contact are introduced. The substrate material, electrode metal system and the structure of photoconductive switch are determined by comparison and project requirements. The common methods of ohmic contact resistivity measurement and the fabrication technology of photoconductive switch are introduced. The contact resistivity of the sample was measured by the method of dot transmission line, the I-V characteristic curve of the ohmic contact was measured by the semiconductor electrical characteristic tester, and the morphology of the metal electrode was scanned by AFM atomic scanning microscope. Finally, the research work is summarized and prospected.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304
本文编号：2428721
[Abstract]:The photoconductive switch (Photoconductive semiconductor switch, PCSS) is a semiconductor material switch that is controlled by light to switch on and off. Photoconductive switch is a kind of optoelectronic conversion device which uses light energy to excite semiconductor material and make its conductivity change and produce electric pulse. The photoconductive switch has the advantages of high power density (MW order of magnitude), fast response speed (ps order of magnitude), low trigger jitter (ps order of magnitude), strong anti-electromagnetic interference ability (good photoelectric isolation), small size and easy integration. It is widely used in many fields, such as high current igniting device, withholding weapon and high power microwave system, precision time synchronization, THz technology, transient test, impulse radar, electromagnetic interference and attack system, etc. Since the birth of photoconductive switches, researchers have been working tirelessly to study the bulk materials of photoconductive switches for different purposes, and the experiments and research on materials have never stopped. Si, in the first generation semiconductor materials, GaAs, in the second generation semiconductor materials, SiC in the third generation semiconductor materials are widely used in photoconductive switches. The electron mobility of GaAs can reach 8500cm2/V s at room temperature, which is much higher than that of Si and SiC. The lifetime of carrier is from O.1ns to 10ns. The experimental data show that the voltage conversion of GaAs photoconductive switch is more efficient than that of Si and SiC. The core part of the photoconductive switch is the ohmic contact between the heavily doped semiconductor active region and the multilayer metal by alloying. The contact resistance of the electrode directly determines the switching speed, efficiency and gain of the photoconductive switch. Therefore, accurate measurement of the parameters of the ohmic contact of the photoconductive switch is a prerequisite for the study of the photoconductive switch. The ohmic contact properties can be characterized by I-V characteristic curve and contact resistivity measurement, or by scanning the morphology of ohmic contact through microscope. In order to obtain good performance, a device must reduce the contact resistivity of the device electrode as much as possible, so as to reduce the pressure drop on the contact and increase the pressure drop in the working part of the device. The research work of this thesis is focused on the fabrication process of GaAs photoconductive switch and the analysis of ohmic contact performance. The research significance, structure and application of photoconductive switch are described in this paper. On this basis, the principle of photoconductive switch and the principle of ohmic contact are introduced. The substrate material, electrode metal system and the structure of photoconductive switch are determined by comparison and project requirements. The common methods of ohmic contact resistivity measurement and the fabrication technology of photoconductive switch are introduced. The contact resistivity of the sample was measured by the method of dot transmission line, the I-V characteristic curve of the ohmic contact was measured by the semiconductor electrical characteristic tester, and the morphology of the metal electrode was scanned by AFM atomic scanning microscope. Finally, the research work is summarized and prospected.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304
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