薄膜光探测器绑定点的几何设计与仿真分析

Geometric design and simulation analysis of the binding site of thin-film photodetector

目前,光器件在硅基衬底上的集成是光电领域的研究热点。将基于表面张力的流体自组装技术应用于薄膜金属-半导体-金属(MSM)光探测器的集成上,其集成效果的优劣与器件绑定点的几何形状有关。为了有效预测薄膜MSM光探测器绑定点的间距和形状对集成效果的影响,利用MATLAB对其集成过程中表面自由能的分布状况进行了仿真分析。首先,在介绍薄膜MSM光探测器的基础上,对其集成过程建立了平移和旋转仿真模型。然后,根据表面自由能与匹配度的线性关系,分别仿真出了不同间距和形状的绑定点在集成过程中匹配度的分布状况图。通过分析匹配度的斜率以及正确装配状态和误装配状态之间的关系,预测两端绑定点间距较长、绑定点形状为梯形时集成效果较好。最后,考虑到薄膜光电器件有可能需要区分正负极的情况,将其两端绑定点设计成不对称形状并进行仿真分析,尽量避免集成过程中出现正负极反接的状态。

Integration of optical devices onto silicon substrate is attracting increasing attention in the field of optoelectronics. The fluidic self-assembly technology was applied to the integration of thin-film metal- semiconductor-metal （MSM） photodetector, the integration results was related to the geometry of the binding site. The spacing and shape of the binding sites on the thin-film MSM photodetector will affect the integration process of device onto the host substrate. In order to effectively predict the effect, MATLAB was used to simulate the distribution of interfacial free energy for the integration process. Firstly, based on the introduction of thin-film MSM photodetector and its integration, a model of translation and rotation during the integration was established for the simulation. Then, according to the linear relationship between the interfacial free energy and the matching degree, the distribution of the matching degree was investigated for the different binding sites with the different spacing and shape. By analyzing the relationship between the slope of the matching degree and the correct-assembly/false-assembly state, it predicted that the integration results would be better when the spacing between the binding sites is longer and the shape of the binding sites is trapezoid. Finally, considering that the thin- film optical devices may have specific requirment of positive and negative contacts, the binding sites with asymmetric shape was designed to avoid the reverse binding connection during the integration process.