發(fā)布時間：2018-04-21 06:50

  本文選題：Si襯底 + 轉(zhuǎn)移　； 參考：《南昌大學(xué)》2015年碩士論文

【摘要】：近年來,半導(dǎo)體照明得到了突飛猛進的發(fā)展,GaN基材料尤其是InGaN/GaN LED在材料生長及LED的制備等方面已日趨成熟�，F(xiàn)如今,LED顯示,背光和照明市場都已啟動,但距離LED燈全面進入家庭照明還有很長的一段路要走,還需要進一步提高其光電性能和降低價格。Si以其低成本,大尺寸,高質(zhì)量,導(dǎo)電,導(dǎo)熱等優(yōu)點,在半導(dǎo)體照明行業(yè)中異軍突起。近年來,本實驗室已經(jīng)研制出了高性能Si襯底GaN基LED并實現(xiàn)產(chǎn)業(yè)化,打破了原來的LED市場格局。但Si襯底也存在一些缺點,即GaN材料之間存在著巨大的晶格失配和熱失配。這使得Si上生長的GaN材料中存在著較大的應(yīng)力,進而影響器件的光電性能。因此Si襯底GaN基LED外延材料生長和器件的制備還有一些問題亟待研究。本論文利用兩種不同的轉(zhuǎn)移工藝而獲得兩組垂直結(jié)構(gòu)的GaN基LED芯片,即一次轉(zhuǎn)移和三次轉(zhuǎn)移工藝。一次轉(zhuǎn)移工藝就是將原生襯底上的GaN薄膜上粘接金屬層然后襯底轉(zhuǎn)移,三次轉(zhuǎn)移工藝是將原生襯底上的GaN外延薄膜粘接在一種柔性材料上然后去除Si襯底,再將其另一面粘接在另一種柔性材料上,最后在去除第二次引人的柔性材料并用共晶將GaN轉(zhuǎn)移至另一Si基板上。本文對這兩組芯片進行研究,分析應(yīng)力分布狀態(tài)對LED光電性能的影響。主要獲得以下研究成果:1用750mA的正向電流對兩組芯片進行24小時,168小時加速老化,老化后發(fā)現(xiàn)三次轉(zhuǎn)移的芯片相比于一次轉(zhuǎn)移的芯片光衰更大。通過分析,發(fā)現(xiàn)光衰的主要來源于光提取效率的下降。2通過XRD對兩組芯片進行掃描,分析發(fā)現(xiàn)三次轉(zhuǎn)移芯片的平整度不夠好。通過臺階儀測試,發(fā)現(xiàn)了三次轉(zhuǎn)移芯片的彎曲度相比于一次轉(zhuǎn)移芯片的確實大很多。利用拉曼譜測芯片的應(yīng)力分布,發(fā)現(xiàn)三次轉(zhuǎn)移芯片應(yīng)力分布均勻,而一次轉(zhuǎn)移芯片應(yīng)力分布均勻。利用電子掃描顯微鏡掃描芯片的截面,發(fā)現(xiàn)三次轉(zhuǎn)移芯片在共晶界面出現(xiàn)縫隙。3本論文研究發(fā)現(xiàn),三次轉(zhuǎn)移工藝由于引人了柔性轉(zhuǎn)移步驟,GaN薄膜的張應(yīng)力能得到徹底釋放,但應(yīng)力釋放的過程中薄膜會發(fā)生嚴一定的彎曲形變,導(dǎo)致共晶粘接時,界面不平粘接強度降低,從而引起老化時界面反射率衰退,出現(xiàn)光衰。
[Abstract]:In recent years, semiconductor lighting has been developed by leaps and bounds. Especially InGaN/GaN LED has become more and more mature in material growth and LED preparation. Today, LED shows that the market for backlight and lighting has started, but there is still a long way to go before LED lights can fully enter home lighting, and further improvements in its photoelectric performance and lower price. Si are needed for its low cost, large size and high quality. Electric conduction, heat conduction and other advantages, in the semiconductor lighting industry springing up. In recent years, GaN based LED on high performance Si substrates has been developed and industrialized in our laboratory, which breaks the original LED market pattern. However, there are some disadvantages in Si substrate, that is, there is a huge lattice mismatch and thermal mismatch between GaN materials. As a result, there is a large stress in the GaN material grown on Si, which affects the photoelectric performance of the device. Therefore, there are still some problems in Si substrate GaN based LED epitaxial material growth and device fabrication. In this paper, two groups of vertical GaN based LED chips are obtained by using two different transfer processes, namely, primary transfer and tertiary transfer. The first transfer process is the bonding of the GaN film on the primary substrate to the metal layer and then the transfer of the substrate. The third transfer process is that the GaN epitaxial film on the primary substrate is bonded to a flexible material and then removed from the Si substrate. Then the other side is bonded to another kind of flexible material, and finally the second attractive flexible material is removed and the GaN is transferred to another Si substrate by eutectic. In this paper, the effects of stress distribution on the optoelectronic properties of LED are studied. The following research results were obtained: 1: 1 accelerated aging of the two groups of chips with forward current of 750mA for 24 hours or 168 hours. After aging, it was found that the chip with three times transfer had greater light decay than the chip with one transfer. Through analysis, it is found that the main source of light decay is the decline of optical extraction efficiency. 2. Scanning the two groups of chips through XRD. The analysis shows that the smoothness of the triple transfer chip is not good enough. It is found that the bending degree of the triple transfer chip is much larger than that of the single transfer chip. Using Raman spectroscopy to measure the stress distribution of the chip, it is found that the stress distribution of the triple transfer chip is uniform, while the stress distribution of the first transfer chip is uniform. By using the cross section of the scanning electron microscope scanning chip, it is found that the third transfer chip has a gap of .3 at the eutectic interface. In this paper, it is found that the tensile stress of the gan film can be completely released by the third transfer process because of the inducement of the flexible transfer step. However, during stress release, the film will be bent and deformed to a certain degree, which will lead to the decrease of the interfacial uneven bonding strength during eutectic bonding, which will result in the decay of the interface reflectivity and the light decay during the aging process.
【學(xué)位授予單位】：南昌大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ133.51;TN312.8

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相關(guān)期刊論文 前1條

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本文編號：1781365