【摘要】：近年來,基于傳統(tǒng)硅工藝的發(fā)展出來的集成電路產(chǎn)業(yè)逐漸遇到了瓶頸,一直指引著集成電路發(fā)展方向的摩爾定律也面臨著不再有效的尷尬境地。硅光電集成技術(shù)被認(rèn)為是解決目前困境的理想方案,然而硅基材料由于其間接帶隙的材料特性,無法成功將其應(yīng)用于片上集成光源領(lǐng)域,阻礙了硅基光電集成技術(shù)的發(fā)展。鍺材料和應(yīng)變鍺材料的載流子遷移率均比硅材料的高,且其與傳統(tǒng)硅工藝兼容,同時,應(yīng)變鍺材料能夠在應(yīng)力作用下轉(zhuǎn)變?yōu)橹苯訋恫牧?這些優(yōu)點使得鍺材料具備在硅基單片光電集成光源上應(yīng)用的潛力,將在未來IC產(chǎn)業(yè)中將發(fā)揮著舉足輕重的作用。本文基于密度泛函-緊束縛近似方法,利用仿真軟件DFTB+得到了應(yīng)變鍺的能帶結(jié)構(gòu),分析在不同應(yīng)力下,鍺材料的能帶結(jié)構(gòu)的變化趨勢,論證了鍺材料在應(yīng)力下作用下轉(zhuǎn)為為直接帶隙材料的變化趨勢,同時,本文還對應(yīng)變鍺材料的應(yīng)力引入機制進行了研究,重點研究了高應(yīng)力氮化硅薄膜,分析其應(yīng)力形成機理并優(yōu)化工藝參數(shù),完成866MPa/-1.38GPa的張應(yīng)變/壓應(yīng)變氮化硅薄膜的制備,為利用高應(yīng)力氮化硅薄膜向鍺薄膜材料引入應(yīng)力奠定理論與實驗基礎(chǔ)。基于高應(yīng)力氮化硅薄膜的研究,本文設(shè)計出一種基于懸浮納米薄膜的應(yīng)變鍺LED,并使用Silvaco仿真軟件對該器件進行了仿真研究。仿真結(jié)果表明,應(yīng)變鍺LED具有良好的光電性能和明顯清晰的光譜響應(yīng),同時其J-V特性、發(fā)光功率、光譜功率密度和光譜峰值波長等器件性能受應(yīng)變量、鍺膜本征層寬度和P/N區(qū)摻雜濃度等關(guān)鍵器件參數(shù)影響較大。其中,輕摻雜應(yīng)變鍺LED的設(shè)計無法滿足實際應(yīng)用的需求,只有采用重?fù)诫s的設(shè)計才能使的器件足夠好的J-V輸出特性、足夠高的輸出功率和足夠大的光譜功率密度;較大的器件本征層寬度能使的器件具有更好的J-V輸出特性、更高的輸出功率和更大的光譜功率密度,但當(dāng)本征層寬度超過了某個值時,則會對器件的性能帶來負(fù)面影響,需全面考慮器件本征層寬度對器件性能帶來的影響;應(yīng)變量的增加能使的器件具有更好的J-V輸出特性、更高的輸出功率和更大的光譜功率密度,特別是當(dāng)鍺材料的應(yīng)變達(dá)到將近1.9%時,其材料屬性便從間接帶隙材料轉(zhuǎn)變?yōu)橹苯訋恫牧?從而大大增加了器件的光電轉(zhuǎn)換效率。基于仿真研究的結(jié)果,利用高應(yīng)力氮化硅薄膜作為應(yīng)力源,本文還對所設(shè)計的基于懸浮納米薄膜的應(yīng)變鍺LED進行了實驗研究。實驗樣品呈現(xiàn)出良好的電致發(fā)光譜,其結(jié)果表明,隨著器件應(yīng)變量的增加,器件的光譜強度不斷增強。本文所制備實驗樣品的最高應(yīng)變量達(dá)到1.92%,實現(xiàn)了鍺材料的直接帶隙發(fā)光,實驗結(jié)果與仿真結(jié)果基本相符。
[Abstract]:In recent years, the development of integrated circuit industry based on traditional silicon technology has gradually encountered a bottleneck, and Moore's law, which has been guiding the development direction of integrated circuit, is facing an awkward situation that is no longer effective. Silicon optoelectronic integration technology is considered to be an ideal solution to the current dilemma. However, silicon based materials can not be successfully applied to the field of on-chip integrated light source due to their material characteristics of indirect bandgap, which hinders the development of silicon based photoelectric integration technology. The carrier mobility of both germanium and strain germanium is higher than that of silicon, and it is compatible with the traditional silicon process. At the same time, the strained germanium can be transformed into a direct bandgap material under stress. These advantages make germanium materials have the potential to be applied in silicon-based monolithic optoelectronic integrated light source and will play an important role in the IC industry in the future. Based on the density functional tight-binding approximation method, the energy band structure of strained germanium is obtained by using the simulation software DFTB, and the variation trend of the band structure of germanium material under different stresses is analyzed. The change trend of germanium into direct-band gap material under stress is demonstrated. At the same time, the stress introduction mechanism of strain germanium material is studied, with emphasis on the high stress silicon nitride film. By analyzing the stress forming mechanism and optimizing the process parameters, the preparation of 866MPa/-1.38GPa tensile strain / compressive strain silicon nitride thin film is completed, which lays a theoretical and experimental foundation for introducing stress into germanium thin film by using high stress silicon nitride film. Based on the study of high stress silicon nitride thin film, a strain germanium LED based on suspension nanocrystalline film is designed and simulated by Silvaco software. The simulation results show that strained germanium LED has good photoelectric performance and obvious spectral response, and its J-V characteristics, luminescent power, spectral power density and spectral peak wavelength are dependent on the performance. The critical device parameters, such as the intrinsic layer width of germanium film and the doping concentration in P / N region, are greatly affected. The design of light-doped strained germanium LED can not meet the requirements of practical applications. Only the design of heavy doping can make the device have sufficient J-V output characteristics, high output power and high spectral power density. The larger intrinsic layer width can make the device have better J-V output characteristics, higher output power and greater spectral power density, but when the intrinsic layer width exceeds a certain value, it will have a negative impact on the performance of the device. The influence of the intrinsic layer width on the device performance should be considered comprehensively, and the increase of the strain can make the device have better J-V output characteristics, higher output power and greater spectral power density. Especially when the strain of germanium material reaches nearly 1.9, the material properties change from indirect band-gap material to direct-band-gap material, thus greatly increasing the photoelectric conversion efficiency of the device. Based on the simulation results, the strain germanium LED based on the suspension nanocrystalline film was studied experimentally by using the high stress silicon nitride film as the stress source. The experimental samples show good electroluminescence spectra. The results show that the spectral intensity of the devices increases with the increase of the device strain. The maximum strain of the sample prepared in this paper is 1.92 and the direct band gap luminescence of germanium is realized. The experimental results are in good agreement with the simulation results.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN312.8;TN304.11

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