光力学主要研究激光和微纳结构机械振动之间的相互作用。GaN基半导体作为宽禁带半导体，是理想的蓝、绿光和紫外光光电材料。利用GaN材料可以开展波长较短的可见光光力学研究，从而进一步缩小微纳结构器件的尺寸和重量，提高其机械振动的频率。现有GaN薄膜大都在蓝宝石、Si、SiC等衬底上异质外延得到。而为了制作GaN光机械微纳结构，需要在折射率较小的SiO2上进行GaN薄膜的制备，既可以满足光限制的要求，也方便采用湿法腐蚀技术制作出悬空的GaN结构。本论文研究了基于选区外延和键合工艺这两种方法制作SiO2上GaN(GaNOI)薄膜的工艺，在此基础上通过干法刻蚀和湿法腐蚀制作了含有InGaN多量子阱的GaN基微盘结构。论文工作取得的主要结果如下：首先，基于金属有机物化学气相沉积技术研究了大尺寸SiO2掩膜上侧向外延GaN的一般规律，得到了表面较为平坦且连平速度较快的GaN材料。表面连平处存在宽度约1 μm、深度约50 nm的V形槽，在V形槽两侧存在宽度约10 μm的GaNOI区域可以用于制作器件。其次，研究了借助苯并环丁烯(BCB)胶的SiO2键合工艺，通过优化夹具、温度、压力等，得到了键合强度较强且稳定的键合材料。之后通过优化HF、HNO3、水混合溶液湿法腐蚀Si衬底的工艺，获得了厚度500 nm，粗糙度为Rq=0.572 nm，Ra=0.450 nm的GaNOI材料，满足了可见光光机械微纳结构制作的要求。最后，通过感应耦合等离子(ICP)干法刻蚀GaN和缓冲氢氟酸(BHF)湿法腐蚀SiO2，制作了含有InGaN/GaN蓝光多量子阱的微盘结构，并测得了微盘的光致荧光 (PL)光谱，验证了GaNOI在制作GaN基可见光光机械微纳结构方面的能力。
Optomechanical system mainly studies the interaction between laser and mechanical vibration of micro/nano structure.As wide band gap semiconductor, GaN based semiconductors are ideal materials for blue, green and ultraviolet optoelectronic devices. The GaN materials can be used to study the optomechanics of shorter wavelength in visible light, thus it can further reduce the size and weight of the micro/nano structure and devices and improve the frequency of their mechanical vibration. The existing GaN films are mostly grown on sapphire, Si, SiC and other substrates. In order to make GaN optical mechanical micro/nano structure, it is necessary to prepare the GaN thin film on the SiO2 with less refractive index, which can meet the requirements of light restriction, and also easy to make the structure of suspended GaN fabricated by wet etching technology. This thesis studies the fabrication of GaN thin films on SiO2 (GaNOI) based on two methods based on the epitaxial lateral overgrowth and bonding process. Based on this process, GaN based microdisk structure containing InGaN multiple quantum wells is fabricated by dry and wet etching.The main results of the work are as follow：Firstly, based on the metal organic chemical vapor deposition (MOCVD) technology, the general rule of the epitaxial lateral overgrowth of GaN with large size SiO2 masks is studied,and the GaN materials with relatively flat surface and faster speed are obtained. There is a 1 μm wide and 50 nm deep V groove on the surface,and about 10 μm wide GaNOI region on both sides of the V groove,which can be used to make optomechanical devices.Secondly, the process of SiO2 bonding with bisbenzocyclobutene (BCB) adhesive is studied. The bonding material with strong bonding strength and stability can be obtained by optimizing the clamping fixture, temperature, pressure and so on. Then,by optimizing the process of HF, HNO3, water mixed solution wet etching the Si substrate,GaNOI material with a thickness of 500 nm is obtained ,and its roughness is Rq=0.572 nm，Ra=0.450 nm which can meet the requirements of the fabrication of visible optomechanical microstructures.Finally, the InGaN/GaN multiple quantum well microdisk in blue light region is fabricated by inductively coupled plasma etching (ICP) of GaN and buffer hydrofluoric acid (BHF) wet etching SiO2 ,and we measured the photoluminescence(PL) spectrum of the microdisk,verifing the ability of GaNOI to make the GaN based visible light optomechanical microstructures.
