GaN基薄膜陽極刻蝕及相關性質的研究
發(fā)布時間：2019-05-16 00:25
【摘要】：GaN是一種寬禁帶直接帶隙半導體材料(Eg=3.4eV),由于其擊穿電壓高、電子漂移速度高、化學性質穩(wěn)定(在室溫下不溶于酸堿溶液),同時擁有介電常數(shù)小以及熱導率高等優(yōu)良的特性,使得GaN材料在制作高溫大功率器件、高頻微波器件、紫外光探測器、微波波導、高亮度發(fā)光二極管、光存儲器件以及高頻、高壓、高溫、抗輻射和大功率器件等領域得到了廣泛的應用。通常,采用有機金屬氣相淀積技術(MOCVD)在藍寶石襯底上異質外延生長GaN基單晶薄膜。然而,氮化鎵和藍寶石襯底之間存在著高的晶格失配率,使得GaN基薄膜具有高缺陷密度和較大的內應力,從而使由GaN基薄膜所制備的器件具有較低的發(fā)光效率、較低的耐壓能力和較低的執(zhí)行能力。由于濕法刻蝕所制備的納米多孔GaN薄膜可以較好的解決上述問題,因此有關納米多孔GaN基薄膜的制備和性質的研究越來越多的受到人們的普遍關注。為此,本文以納米多孔GaN基薄膜為主線,系統(tǒng)地研究了納米多孔和納米空腔對GaN基薄膜光電特性的影響。其主要研究內容如下:(1)由于使用電化學刻蝕技術制備納米多孔GaN薄膜所選取的刻蝕溶液(酸堿溶液)具有不安全、不環(huán)保等缺點,因此用中性溶液替代酸堿溶液成為必然。為此,我們研究了 GaN薄膜在中性NaN03溶液中進行刻蝕,探究在中性溶液中刻蝕的影響因素;利用高分辨透射電子顯微鏡(HRTEM)定量計算納米多孔誘使GaN薄膜內應力的變化量,并用拉曼光譜進行驗證。(2)多孔GaN薄膜最重要的用途之一就是進行GaN薄膜或InGaN/GaN超晶格和多量子阱結構的再生長。由于再生長的溫度通常在800℃到1050℃之間進行,因此系統(tǒng)地研究NH3氣氛中對納米多孔GaN薄膜熱退火的影響具有重要的理論和實際意義。我們對多孔GaN薄膜在NH3氣體氛圍下進行高溫(800℃)退火處理,研究發(fā)現(xiàn)退火后的納米多孔GaN薄膜轉變?yōu)榧{米空腔GaN薄膜。為此,我們系統(tǒng)地研究了退火時間對孔洞的影響以及由多孔向空腔轉變的轉化機制;采用HRTEM圖像和拉曼光譜技術定性和定量分析了退火對GaN薄膜內應力的影響。(3)生長在藍寶石襯底上的具有InGaN/GaN多量子阱結構的GaN基薄膜具有較高的缺陷密度和較大的內應力,因此要想提高其發(fā)光效率設法降低薄膜缺陷密度和釋放內應力是必不可少的。由于濕法刻蝕可降低薄膜內缺陷密度和釋放內應力等優(yōu)點,為此,我們在酸性溶液中對具有InGaN/GaN多量子結構的GaN基薄膜進行刻蝕,并對其刻蝕機理進行了系統(tǒng)的分析;利用多種表征方法探究了影響GaN基LED材料刻蝕的因素,并在此基礎上通過變電壓的方式制備自支撐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，
本文編號：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，
本文編號：2477878
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