某型低接觸電阻率異面GaAs半導體光導開關的研究
發(fā)布時間：2019-02-23 10:14
【摘要】：光導開關(Photoconductive semiconductor switch, PCSS)也就是通過光控制導通與關斷的半導體材料開關。光導開關是一種利用光能量激勵半導體材料,使其電導率發(fā)生變化而產生電脈沖的光電轉換器件。光導開關具有功率密度高(MW量級)、響應速度快(ps量級)、觸發(fā)抖動低(ps量級)、抗電磁干擾能力強(良好的光電隔離)、體積小、易集成的優(yōu)點。在大電流點火裝置、拒止武器和高功率微波系統(tǒng)、精密時間同步、THz技術、瞬態(tài)測試、沖激雷達、電磁干擾與攻擊系統(tǒng)等領域應用廣泛。光導開關誕生以后,研究人員就孜孜不倦的研究著不同用途的光導開關的體材料,對于材料的實驗和研究從未停止。第一代半導體材料中的Si,第二代半導體材料中的GaAs,第三代半導體材料中的SiC都被廣泛應用到光導開關中。常溫下GaAs的電子遷移率可達8500cm2/V·s,比Si和SiC都要高得多,載流子的壽命為O.1ns到10ns,實驗數(shù)據(jù)表明,對于特定波長的光激勵,GaAs光導開關的電壓轉換有著更高的效率。光導開關的核心部分是重摻雜半導體有源區(qū)與多層金屬經合金化形成電極的歐姆接觸。電極接觸電阻的大小直接決定了光導開關的開關速度、效率和增益等性能,因此準確的測量光導開關歐姆接觸的參數(shù)是研究光導開關的先決條件。歐姆接觸性能的表征可以通過Ⅰ-Ⅴ特性曲線和接觸電阻率測量來體現(xiàn),也可以通過顯微鏡來掃描其形貌特征來直觀表現(xiàn)。一個器件要想獲得良好的性能,必須盡可能的降低器件電極的接觸電阻率,從而減小接觸上的壓降,增大器件工作部分的壓降。本論文的研究工作是圍繞GaAs光導開關的制作工藝和歐姆接觸性能分析研究展開的。論文敘述了光導開關的研究意義、結構和應用,在此基礎上,介紹了光導開關的原理和歐姆接觸的原理；通過對比和項目的要求確定了光導開關的襯底材料、電極金屬體系和光導開關的結構；介紹了常見的歐姆接觸電阻率測量的方法和光導開關的制作工藝;用圓點傳輸線測量方法對樣品的接觸電阻率進行了測量,用半導體電學特性測試儀測量了歐姆接觸的I-V特性曲線,并且用AFM原子掃描顯微鏡對金屬電極的形貌進行了掃描；論文最后對研究工作進行了總結和展望。
[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.
【學位授予單位】：合肥工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN304
本文編號：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.
【學位授予單位】：合肥工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN304
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，本文編號：2428721
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