自由支撐GaN基LED薄膜發(fā)光性能的研究
發(fā)布時(shí)間：2018-09-10 09:45
【摘要】：目前硅襯底Ga N基LED外延薄膜緩減張應(yīng)力和防止裂紋的方法主要有兩種:其一為使用圖形硅襯底,其二為生長(zhǎng)較厚的鋁鎵氮緩沖層,這兩種方法各有優(yōu)缺點(diǎn)。盡管圖形硅襯底Ga N基LED已經(jīng)實(shí)現(xiàn)批量生產(chǎn)并逐漸為市場(chǎng)所接受,然而它還有大量的科學(xué)技術(shù)問(wèn)題有待解決,諸多研究空白值得進(jìn)行深入研究。其中,研究清楚單個(gè)圖形內(nèi)不同微區(qū)的發(fā)光性能及應(yīng)力狀態(tài)、襯底和緩沖層與量子阱層的應(yīng)力交互作用及其對(duì)發(fā)光性能的影響等問(wèn)題,對(duì)于提高硅襯底Ga N外延薄膜質(zhì)量和器件性能具有重要指導(dǎo)意義,因此本文系統(tǒng)研究了圖形硅襯底Ga N基LED薄膜去除襯底及Al N緩沖層后單個(gè)圖形內(nèi)微區(qū)發(fā)光及應(yīng)力變化。光致發(fā)光譜是研究Ga N基LED的一種重要研究手段,然而硅襯底是不透光襯底,它對(duì)可見(jiàn)光具有一定的反射率,在硅襯底上外延的LED薄膜其光致發(fā)光譜會(huì)存在明顯的干涉現(xiàn)象,這給準(zhǔn)確的研究硅襯底LED的發(fā)光性能帶來(lái)極大困難。本文,利用Ga N特有的特性,研究了一種獲得無(wú)干涉的硅襯底LED薄膜PL譜的測(cè)試方法,為準(zhǔn)確的研究硅襯底Ga N基薄膜發(fā)光性能帶來(lái)極大便利。本文的主要研究?jī)?nèi)容和結(jié)論如下:1、去除圖形硅襯底后,自由支撐的LED薄膜朝襯底方向呈柱面彎曲狀態(tài),且相鄰圖形的柱面彎曲方向不一致,當(dāng)進(jìn)一步去除Al N緩沖層后薄膜會(huì)由彎曲變?yōu)槠秸?、LED薄膜在去除硅襯底前后同一圖形內(nèi)不同位置的PL譜具有顯著差異,而當(dāng)去除氮化鋁緩沖層后不同位置的PL譜會(huì)基本趨于一致.3、LED薄膜每一位置的PL譜在去除硅襯底后均出現(xiàn)明顯紅移,進(jìn)一步去除AlN緩沖層后PL譜出現(xiàn)程度不一的微小藍(lán)移.4、自由支撐的LED薄膜去除氮化鋁緩沖層后PL光強(qiáng)隨激光激發(fā)密度變化的發(fā)光強(qiáng)度光衰減(Droop)得到改善。5、在PL譜的探測(cè)光路上采用經(jīng)濕法粗化的GaN薄膜作為消干片,能基本徹底消除硅襯底Ga N基薄膜PL譜中的明顯干涉現(xiàn)象,該方法消干效果好于目前文已報(bào)道的Ga N薄膜光譜的消干方法。
[Abstract]:At present, there are two main methods to reduce tensile stress and prevent cracks in Ga N-substrate LED epitaxial thin films on silicon substrate. One is to use patterned silicon substrate, the other is to grow thick aluminum-gallium nitrogen buffer layer. These two methods have their own advantages and disadvantages. Although the graphic silicon substrate Ga N-base LED has realized batch production and has gradually been accepted by the market, it still has a large number of scientific and technological problems to be solved, and many research gaps are worthy of further study. Among them, the luminescence properties and stress states of different microregions in a single figure, the stress interaction between substrate and buffer layer and quantum well layer, and their effects on luminescence performance are studied. It is important to improve the quality and device performance of Ga N epitaxial films on Si substrates. Therefore, the luminescence and stress changes in a single image microregion after the removal of substrate and Al N buffer layer from Ga N based LED films on graphically silicon substrates have been systematically studied in this paper. Photoluminescence spectroscopy is an important method to study Ga N-base LED. However, silicon substrate is an impervious substrate, which has a certain reflectivity to visible light. The photoluminescence spectra of LED films epitaxial on silicon substrates have obvious interference phenomenon. This makes it very difficult to accurately study the luminescent properties of Si substrate LED. In this paper, using the characteristic of Ga N, a method of obtaining PL spectra of LED films on Si substrates without interference is studied, which brings great convenience to the accurate study of the luminescence properties of Ga N-base films on Si substrates. The main contents and conclusions of this paper are as follows: 1. After removing the patterned silicon substrate, the free-supported LED film is cylindrical bending towards the substrate, and the cylindrical bending direction of the adjacent figure is not consistent. When the buffer layer of Al N is removed further, the film will change from bending to leveling. The PL spectra of different positions in the same figure before and after the removal of silicon substrate have significant differences. When aluminum nitride buffer layer is removed, the PL spectra at different positions tend to be consistent. The PL spectra of each position of the thin film tend to red shift obviously after the removal of silicon substrate. After further removing the AlN buffer layer, the PL spectrum appears a little blue shift of varying degrees. 4. After the free supported LED film removes the aluminum nitride buffer layer, the luminescence intensity attenuation (Droop) of PL with the laser excitation density is improved. 5. In the PL spectrum, the light intensity attenuation (Droop) of the PL light intensity changes with the laser excitation density is improved. Using GaN thin film coarsened by wet process as a dry elimination chip, The obvious interference phenomenon in the PL spectrum of Ga N based films on silicon substrate can be eliminated completely. This method is better than the previous reported method in eliminating the dry spectrum of Ga N thin films.
【學(xué)位授予單位】：南昌大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB383.2;TN312.8
本文編號(hào)：2234088
[Abstract]:At present, there are two main methods to reduce tensile stress and prevent cracks in Ga N-substrate LED epitaxial thin films on silicon substrate. One is to use patterned silicon substrate, the other is to grow thick aluminum-gallium nitrogen buffer layer. These two methods have their own advantages and disadvantages. Although the graphic silicon substrate Ga N-base LED has realized batch production and has gradually been accepted by the market, it still has a large number of scientific and technological problems to be solved, and many research gaps are worthy of further study. Among them, the luminescence properties and stress states of different microregions in a single figure, the stress interaction between substrate and buffer layer and quantum well layer, and their effects on luminescence performance are studied. It is important to improve the quality and device performance of Ga N epitaxial films on Si substrates. Therefore, the luminescence and stress changes in a single image microregion after the removal of substrate and Al N buffer layer from Ga N based LED films on graphically silicon substrates have been systematically studied in this paper. Photoluminescence spectroscopy is an important method to study Ga N-base LED. However, silicon substrate is an impervious substrate, which has a certain reflectivity to visible light. The photoluminescence spectra of LED films epitaxial on silicon substrates have obvious interference phenomenon. This makes it very difficult to accurately study the luminescent properties of Si substrate LED. In this paper, using the characteristic of Ga N, a method of obtaining PL spectra of LED films on Si substrates without interference is studied, which brings great convenience to the accurate study of the luminescence properties of Ga N-base films on Si substrates. The main contents and conclusions of this paper are as follows: 1. After removing the patterned silicon substrate, the free-supported LED film is cylindrical bending towards the substrate, and the cylindrical bending direction of the adjacent figure is not consistent. When the buffer layer of Al N is removed further, the film will change from bending to leveling. The PL spectra of different positions in the same figure before and after the removal of silicon substrate have significant differences. When aluminum nitride buffer layer is removed, the PL spectra at different positions tend to be consistent. The PL spectra of each position of the thin film tend to red shift obviously after the removal of silicon substrate. After further removing the AlN buffer layer, the PL spectrum appears a little blue shift of varying degrees. 4. After the free supported LED film removes the aluminum nitride buffer layer, the luminescence intensity attenuation (Droop) of PL with the laser excitation density is improved. 5. In the PL spectrum, the light intensity attenuation (Droop) of the PL light intensity changes with the laser excitation density is improved. Using GaN thin film coarsened by wet process as a dry elimination chip, The obvious interference phenomenon in the PL spectrum of Ga N based films on silicon substrate can be eliminated completely. This method is better than the previous reported method in eliminating the dry spectrum of Ga N thin films.
【學(xué)位授予單位】：南昌大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB383.2;TN312.8
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 李述體,王立,辛勇,彭學(xué)新,熊傳兵,姚冬敏,江風(fēng)益;MOCVD生長(zhǎng)的GaN單晶膜的藍(lán)帶發(fā)光研究[J];發(fā)光學(xué)報(bào);2000年01期
，本文編號(hào)：2234088
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