基于偏振参数成像的半导体发光芯片检测方法研究

【作者】 陈伟；

【导师】 刘学峰；

【作者基本信息】 南京理工大学 ， 光电信息工程（专业学位）， 2023， 硕士

【摘要】 近年来,半导体发光芯片技术迅猛发展,其应用范围已从最初的科学研究领域拓展到工业制造、生物医学、航空航天、民生国防等众多领域。通常半导体发光芯片的质量好坏,可以用光束特性参数进行描述,如光束的光谱特征、功率比、光斑形状以及能量分布等,而这些参数普遍与芯片发光端面形态、缺陷及杂质分布等结构特性紧密关联。光学显微成像具有结构简单、快捷高效、成本低、适应性强等优势,是实现发光芯片检测的潜在方案之一。但由于光学衍射极限限制,传统光学显微系统难以满足对半导体发光芯片端面纳米级层状结构及亚微米级杂质及缺陷的检测要求;另外,传统光学成像采用的对场景光强信号直接均匀采样与再现的机制,以及为避免成像元件(如CCD)被灼烧失效而对芯片光强进行衰减的操作,导致发光芯片检测关键信息丢失且信息维度单一。针对上述问题,本文提出采用偏振参数成像技术,通过收集多维度光子状态参数图谱代替单一光强信息,并对多维信息进行综合研究分析,在单一测试系统中同时实现了芯片端面结构与近场光斑特征的高分辨率、高准确性检测。本文主要内容安排如下。首先,根据偏振成像基本理论,建立了基于偏振参数成像的芯片端面结构和近场光斑检测理论模型,并分别推导了相位延迟、方位角以及斯托克斯参数等多维度偏振参数表达式。其次,根据建立的模型,搭建了基于偏振参数显微成像的半导体发光芯片检测系统。为了更好的证明方案的可行性,本论文设计制备了双弯折脊波导SLD,并利用数值模拟方法获得了该SLD的近场光斑特征信息。最后,利用搭建的系统对制备的SLD端面结构及近场发光光斑进行了检测。实验结果表明,根据收集到的多维度高准确性偏振参数图,我们可以清晰地分辨SLD端面上的杂质、波导结构以及金属覆盖层;可以判断出SLD的偏振状态,并还原出该SLD的近场光斑形状,还观察到与模拟结果一致的光斑左右不对称性以及由于结构缺陷导致的拖尾处断裂,从而在端面上对缺陷位置进行精确定位。本文所搭建的偏振参数显微成像系统可以同时对发光芯片端面结构以及近场光斑特征进行检测。该检测方法具有结构简单、成本低且对芯片无破坏等优势,为半导体发光芯片高效高准确性检测提供了一种新的技术方案选择。更多还原

【Abstract】 In recent years,with the rapid development of semiconductor light-emitting chip technology,its application scope has been expanded from the initial field of scientific research to industrial manufacturing,biomedicine,aerospace,livelihood and national defense and many other fields.Generally,the quality of semiconductor light-emitting chips can be described by beam characteristic parameters,such as the spectral characteristics of the beam,power ratio,spot shape and energy distribution,etc.,and these parameters are generally closely related to the chip light-emitting end face morphology,defects and impurity distribution and other structural characteristics.Optical microscopy imaging has the advantages of simple structure,high speed and efficiency,low cost,and high adaptability,which is one of the potential solutions to realize the detection of light-emitting chips.However,due to the limitation of optical diffraction,it is difficult for the traditional optical microscopic system to meet the requirements of detection of nano-level layered structures and submicron-level impurities and defects on the end faces of semiconductor light-emitting chips.In addition,conventional optical imaging uses a mechanism of direct uniform sampling and reproduction of the light intensity of the scene,as well as the operation of the attenuation of light intensity in order to avoid the failure of imaging elements(such as CCD)by burning,resulting in the loss of key information and a single dimension of information for light-emitting chip detection.To address the above problems,this thesis proposes the use of polarization parametric imaging technology to simultaneously achieve high-resolution and high-accuracy detection of the end-face structures and near-field spot features in a single detection system by collecting multi-dimensional photon-state parametric images,instead of the single light intensity,and conducting comprehensive study and analysis of multi-dimensional information.The main contents of this thesis are arranged as follows.Firstly,according to the basic theory of polarization imaging,the theoretical models of chip end structure and near-field spot detection based on polarization parametric imaging are established,and multi-dimensional polarization parametric expressions such as phase delay,azimuth angle and Stokes parameter are derived respectively.Secondly,according to the established model,a detection system for semiconductor light-emitting chip based on polarization parametric imaging is built.In order to better demonstrate the feasibility of the scheme,a double-bending ridge waveguide SLD is designed and fabricated in this thesis,and the near-field spot characteristic information of this SLD is obtained by numerical simulation method.Finally,the end-face structure and near-field spots of the prepared SLD were detected by the constructed system.The experimental results show that the impurities,waveguide structure and metal covering layer on the end face of SLD can be clearly distinguished by the collected multi-dimensional polarization parametric graphs with high accuracy.The polarization state of the SLD is determined,the near-field spot shape of the SLD can be restored,and the asymmetry of the spot which is greatly consistent with the simulation results,and the fracture at the tail caused by the structural defect are also observed,so as to precisely locate the defect position on the end face.The polarization parametric imaging system established in this thesis can simultaneously detect the end-face structure of the light-emitting chip and the characteristics of the near-field spot.The detection method has the advantages of simple structure,low cost and no damage to the chip,which provides a new technical solution option for highly efficient and accurate detection of semiconductor light-emitting chips.更多还原