【摘要】：LED襯底決定了LED器件的制造路線,并且會(huì)嚴(yán)重影響LED器件的綜合性能。開發(fā)高質(zhì)量的自支撐GaN襯底是未來高效大功率LED領(lǐng)域重要發(fā)展趨勢(shì)。然而,GaN襯底很難用常規(guī)的單晶生長(zhǎng)技術(shù)進(jìn)行制備,而是多采用在藍(lán)寶石襯底上進(jìn)行外延生長(zhǎng)薄膜。異質(zhì)外延所產(chǎn)生的熱膨脹系數(shù)差別和晶格失配會(huì)大大降低GaN薄膜質(zhì)量。ZnO和GaN具有相同的六方晶格結(jié)構(gòu),且晶格常數(shù)和熱膨脹系數(shù)也很相近。因此,高質(zhì)量的ZnO薄膜能作為GaN薄膜生長(zhǎng)的緩沖層。 本文以氧化鋅陶瓷靶材為原料,氧氣和氬氣分別作為反應(yīng)和濺射氣體,根據(jù)正交實(shí)驗(yàn)原理采用磁控濺射方法在藍(lán)寶石襯底上制備優(yōu)質(zhì)GaN薄膜生長(zhǎng)用氧化鋅緩沖層薄膜,主要研究了濺射溫度、所通入氧氣與氬氣的比例,濺射氣壓、濺射時(shí)間及退火處理對(duì)氧化鋅薄膜的結(jié)晶性能、表面形貌、光致發(fā)光性能和薄膜厚度的影響。通過采用SEM、AFM、XRD,PL譜測(cè)試儀、臺(tái)階儀等儀器來測(cè)量表征氧化鋅薄膜的性能。 實(shí)驗(yàn)結(jié)果表明:根據(jù)正交試驗(yàn)原理得出,溫度變化對(duì)氧化鋅薄膜的結(jié)構(gòu)和結(jié)晶性及光致發(fā)光性能影響最大。當(dāng)溫度為250℃的時(shí)候,氧化鋅薄膜的綜合性能較好;比較分析了在空氣氛圍和氮?dú)夥諊逻M(jìn)行退火處理對(duì)樣品性能的影響,實(shí)驗(yàn)表明退火處理能改善氧化鋅薄膜的結(jié)晶性和光致發(fā)光性能,能增強(qiáng)薄膜與基底的結(jié)合力;與在氮?dú)夥諊鷹l件下進(jìn)行退火處理相比,在空氣氛圍條件下退火,ZnO薄膜性能更好。溫度為800℃,保溫1小時(shí),空氣氛圍中退火,ZnO薄膜(002)取向性顯著提高,FWHM值僅為0.2o,晶粒更加均勻細(xì)小;在溫度為600℃,保溫1h,空氣氛圍條件下退火,ZnO薄膜的光致發(fā)光性能最好。 最后本文得出,磁控濺射法制備高質(zhì)量的氧化鋅緩沖層工藝為:氧氬氣體流量比例為O2:Ar=2:1、濺射氣壓為1Pa、薄膜沉積溫度為250℃、薄膜沉積時(shí)間為2h,退火氣氛為空氣,退火溫度介于600℃至800℃之間且保溫1h。有望在高質(zhì)量GaN襯底生長(zhǎng)用緩沖層領(lǐng)域得到廣泛應(yīng)用。
[Abstract]:LED substrate determines the manufacturing route of LED devices, and will seriously affect the comprehensive performance of LED devices. Developing high-quality self-supporting GaN substrates is an important trend in the field of high efficiency and high power LED in the future. However, GaN substrates are difficult to be prepared by conventional single crystal growth techniques, and epitaxial films are often grown on sapphire substrates. The difference of thermal expansion coefficient and lattice mismatch caused by heteroepitaxial epitaxy will greatly reduce the quality of GaN film. ZnO and GaN have the same hexagonal lattice structure and the lattice constant and thermal expansion coefficient are very similar. Therefore, high quality ZnO film can be used as a buffer layer for GaN thin film growth. In this paper, zinc oxide buffer films were prepared on sapphire substrates by magnetron sputtering with zinc oxide ceramic target as raw material, oxygen and argon as reactive and sputtering gases, respectively, according to the principle of orthogonal experiment. The effects of sputtering temperature, the ratio of oxygen to argon, sputtering pressure, sputtering time and annealing on the crystalline properties, surface morphology, photoluminescence properties and thickness of ZnO thin films were studied. The properties of ZnO films were measured by means of SEM,AFM,XRD,PL spectrometer and step meter. The experimental results show that the effect of temperature on the structure, crystallinity and photoluminescence properties of ZnO films is the greatest according to the principle of orthogonal experiment. When the temperature is 250 鈩，

本文編號(hào)：2332816