GaN基薄膜阳极刻蚀及相关性质的研究
发布时间：2019-05-16 00:25
【摘要】：GaN是一种宽禁带直接带隙半导体材料(Eg=3.4eV),由于其击穿电压高、电子漂移速度高、化学性质稳定(在室温下不溶于酸碱溶液),同时拥有介电常数小以及热导率高等优良的特性,使得GaN材料在制作高温大功率器件、高频微波器件、紫外光探测器、微波波导、高亮度发光二极管、光存储器件以及高频、高压、高温、抗辐射和大功率器件等领域得到了广泛的应用。通常,采用有机金属气相淀积技术(MOCVD)在蓝宝石衬底上异质外延生长GaN基单晶薄膜。然而,氮化镓和蓝宝石衬底之间存在着高的晶格失配率,使得GaN基薄膜具有高缺陷密度和较大的内应力,从而使由GaN基薄膜所制备的器件具有较低的发光效率、较低的耐压能力和较低的执行能力。由于湿法刻蚀所制备的纳米多孔GaN薄膜可以较好的解决上述问题,因此有关纳米多孔GaN基薄膜的制备和性质的研究越来越多的受到人们的普遍关注。为此,本文以纳米多孔GaN基薄膜为主线,系统地研究了纳米多孔和纳米空腔对GaN基薄膜光电特性的影响。其主要研究内容如下:(1)由于使用电化学刻蚀技术制备纳米多孔GaN薄膜所选取的刻蚀溶液(酸碱溶液)具有不安全、不环保等缺点,因此用中性溶液替代酸碱溶液成为必然。为此,我们研究了 GaN薄膜在中性NaN03溶液中进行刻蚀,探究在中性溶液中刻蚀的影响因素;利用高分辨透射电子显微镜(HRTEM)定量计算纳米多孔诱使GaN薄膜内应力的变化量,并用拉曼光谱进行验证。(2)多孔GaN薄膜最重要的用途之一就是进行GaN薄膜或InGaN/GaN超晶格和多量子阱结构的再生长。由于再生长的温度通常在800℃到1050℃之间进行,因此系统地研究NH3气氛中对纳米多孔GaN薄膜热退火的影响具有重要的理论和实际意义。我们对多孔GaN薄膜在NH3气体氛围下进行高温(800℃)退火处理,研究发现退火后的纳米多孔GaN薄膜转变为纳米空腔GaN薄膜。为此,我们系统地研究了退火时间对孔洞的影响以及由多孔向空腔转变的转化机制;采用HRTEM图像和拉曼光谱技术定性和定量分析了退火对GaN薄膜内应力的影响。(3)生长在蓝宝石衬底上的具有InGaN/GaN多量子阱结构的GaN基薄膜具有较高的缺陷密度和较大的内应力,因此要想提高其发光效率设法降低薄膜缺陷密度和释放内应力是必不可少的。由于湿法刻蚀可降低薄膜内缺陷密度和释放内应力等优点,为此,我们在酸性溶液中对具有InGaN/GaN多量子结构的GaN基薄膜进行刻蚀,并对其刻蚀机理进行了系统的分析;利用多种表征方法探究了影响GaN基LED材料刻蚀的因素,并在此基础上通过变电压的方式制备自支撑GaN基LED薄膜。
[Abstract]:GaN is a wide band gap semiconductor material (Eg=3.4eV). Because of its high breakdown voltage, high electron drift speed and stable chemical properties (insoluble in acid-base solution at room temperature), At the same time, it has the excellent characteristics of small dielectric constant and high thermal conductivity, which makes GaN materials in the fabrication of high temperature and high power devices, high frequency microwave devices, UV detector, microwave waveguides, high brightness light emitting diode, optical storage devices and high frequency. High pressure, high temperature, radiation resistance and high power devices have been widely used. In general, GaN based single crystal thin films were grown on sapphire substrate by organometallic vapor deposition (MOCVD). However, there is a high lattice mismatch between gallium nitride and sapphire substrate, which makes the GaN based thin films have high defect density and large internal stress, so that the devices prepared by GaN based thin films have lower luminous efficiency. Lower pressure resistance and lower execution ability. Because the nano-porous GaN thin films prepared by wet etching can solve the above problems, more and more attention has been paid to the preparation and properties of nano-porous GaN based thin films. In this paper, the effects of nano-porous GaN based thin films on the photoelectric properties of GaN based thin films were systematically studied. The main research contents are as follows: (1) the etched solution (acid-base solution) selected for the preparation of nano-porous GaN thin films by electrochemical etch technology has some shortcomings, such as unsafe, unenvironmentally friendly and so on. Therefore, it is necessary to replace acid-base solution with neutral solution. For this reason, we studied the etch of GaN thin films in neutral NaN03 solution, and explored the influencing factors of etch in neutral solution. The variation of stress in GaN thin films induced by nano-pores was quantitatively calculated by high resolution transmission electron microscope (HRTEM). Raman spectroscopy is used to verify. (2) one of the most important uses of porous GaN thin films is to regrow GaN thin films or InGaN/ gan superlattices and multiple quantum well structures. Because the regrowth temperature is usually between 800 鈩，
本文编号：2477878
[Abstract]:GaN is a wide band gap semiconductor material (Eg=3.4eV). Because of its high breakdown voltage, high electron drift speed and stable chemical properties (insoluble in acid-base solution at room temperature), At the same time, it has the excellent characteristics of small dielectric constant and high thermal conductivity, which makes GaN materials in the fabrication of high temperature and high power devices, high frequency microwave devices, UV detector, microwave waveguides, high brightness light emitting diode, optical storage devices and high frequency. High pressure, high temperature, radiation resistance and high power devices have been widely used. In general, GaN based single crystal thin films were grown on sapphire substrate by organometallic vapor deposition (MOCVD). However, there is a high lattice mismatch between gallium nitride and sapphire substrate, which makes the GaN based thin films have high defect density and large internal stress, so that the devices prepared by GaN based thin films have lower luminous efficiency. Lower pressure resistance and lower execution ability. Because the nano-porous GaN thin films prepared by wet etching can solve the above problems, more and more attention has been paid to the preparation and properties of nano-porous GaN based thin films. In this paper, the effects of nano-porous GaN based thin films on the photoelectric properties of GaN based thin films were systematically studied. The main research contents are as follows: (1) the etched solution (acid-base solution) selected for the preparation of nano-porous GaN thin films by electrochemical etch technology has some shortcomings, such as unsafe, unenvironmentally friendly and so on. Therefore, it is necessary to replace acid-base solution with neutral solution. For this reason, we studied the etch of GaN thin films in neutral NaN03 solution, and explored the influencing factors of etch in neutral solution. The variation of stress in GaN thin films induced by nano-pores was quantitatively calculated by high resolution transmission electron microscope (HRTEM). Raman spectroscopy is used to verify. (2) one of the most important uses of porous GaN thin films is to regrow GaN thin films or InGaN/ gan superlattices and multiple quantum well structures. Because the regrowth temperature is usually between 800 鈩，
本文编号：2477878
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