基于悬浮纳米薄膜的应变锗LED研究
发布时间：2018-07-23 13:17
【摘要】：近年来,基于传统硅工艺的发展出来的集成电路产业逐渐遇到了瓶颈,一直指引着集成电路发展方向的摩尔定律也面临着不再有效的尴尬境地。硅光电集成技术被认为是解决目前困境的理想方案,然而硅基材料由于其间接带隙的材料特性,无法成功将其应用于片上集成光源领域,阻碍了硅基光电集成技术的发展。锗材料和应变锗材料的载流子迁移率均比硅材料的高,且其与传统硅工艺兼容,同时,应变锗材料能够在应力作用下转变为直接带隙材料,这些优点使得锗材料具备在硅基单片光电集成光源上应用的潜力,将在未来IC产业中将发挥着举足轻重的作用。本文基于密度泛函-紧束缚近似方法,利用仿真软件DFTB+得到了应变锗的能带结构,分析在不同应力下,锗材料的能带结构的变化趋势,论证了锗材料在应力下作用下转为为直接带隙材料的变化趋势,同时,本文还对应变锗材料的应力引入机制进行了研究,重点研究了高应力氮化硅薄膜,分析其应力形成机理并优化工艺参数,完成866MPa/-1.38GPa的张应变/压应变氮化硅薄膜的制备,为利用高应力氮化硅薄膜向锗薄膜材料引入应力奠定理论与实验基础。基于高应力氮化硅薄膜的研究,本文设计出一种基于悬浮纳米薄膜的应变锗LED,并使用Silvaco仿真软件对该器件进行了仿真研究。仿真结果表明,应变锗LED具有良好的光电性能和明显清晰的光谱响应,同时其J-V特性、发光功率、光谱功率密度和光谱峰值波长等器件性能受应变量、锗膜本征层宽度和P/N区掺杂浓度等关键器件参数影响较大。其中,轻掺杂应变锗LED的设计无法满足实际应用的需求,只有采用重掺杂的设计才能使的器件足够好的J-V输出特性、足够高的输出功率和足够大的光谱功率密度;较大的器件本征层宽度能使的器件具有更好的J-V输出特性、更高的输出功率和更大的光谱功率密度,但当本征层宽度超过了某个值时,则会对器件的性能带来负面影响,需全面考虑器件本征层宽度对器件性能带来的影响;应变量的增加能使的器件具有更好的J-V输出特性、更高的输出功率和更大的光谱功率密度,特别是当锗材料的应变达到将近1.9%时,其材料属性便从间接带隙材料转变为直接带隙材料,从而大大增加了器件的光电转换效率。基于仿真研究的结果,利用高应力氮化硅薄膜作为应力源,本文还对所设计的基于悬浮纳米薄膜的应变锗LED进行了实验研究。实验样品呈现出良好的电致发光谱,其结果表明,随着器件应变量的增加,器件的光谱强度不断增强。本文所制备实验样品的最高应变量达到1.92%,实现了锗材料的直接带隙发光,实验结果与仿真结果基本相符。
[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.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN312.8;TN304.11
本文编号：2139533
[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.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN312.8;TN304.11
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