Data_Sheet_1_Modeling a Thick Hydrogenated Amorphous Silicon Substrate for Ionizing Radiation Detectors.PDF

There is currently a renewed interest in hydrogenated amorphous silicon (a-Si:H) for use in particle detection applications. Whilst this material has been comprehensively investigated from a numerical perspective within the context of photovoltaic and imaging applications, the majority of work related to its application in particle detection has been limited to experimental studies. In this study, a material model to mimic the electrical and charge collection behavior of a-Si:H is developed using the SYNOPSYS©Technology Computer Aided Design (TCAD) simulation tool Sentaurus. The key focus of the model is concerned with the quasi-continuous defect distribution of acceptor and donor defects near the valence and conduction bands (tails states) and a Gaussian distribution of acceptor and donor defects within the mid-gap with the main parameters being the defect energy level, capture cross-section, and trap density. Currently, Sentaurus TCAD offers Poole-Frenkel mobility and trap models, however, these were deemed to be incompatible with thick a-Si:H substrates. With the addition of a fitting function, the model was able to provide acceptable agreement (within 10 nA cm−2) between simulated and experimental leakage current density for a-Si:H substrates with thicknesses of 12 and 30 μm. Additional transient simulations performed to mimic the response of the 12 μm thick device demonstrated excellent agreement (1%) with experimental data found in the literature in terms of the operating voltage required to deplete thick a-Si:H devices. The a-Si:H model developed in this work provides a method of optimizing a-Si:H based devices for particle detection applications.

当前，对于氢化非晶硅（a-Si:H）在粒子检测应用中的使用，再次引起了广泛关注。尽管从数值角度而言，该材料在光伏和成像应用方面的研究已相当全面，但与其在粒子检测应用中相关的大多数研究仍局限于实验研究。在本研究中，利用SYNOPSYS©技术计算机辅助设计（TCAD）模拟工具Sentaurus，开发了一种模拟a-Si:H的电学和电荷收集行为的材料模型。模型的关键关注点在于近价带和导带（尾态）的受主和施主缺陷的准连续分布，以及在中隙内的受主和施主缺陷的高斯分布，主要参数包括缺陷能级、捕获截面积和陷阱密度。目前，Sentaurus TCAD提供了Poole-Frenkel迁移率和陷阱模型，但这些被认为与厚a-Si:H衬底不兼容。通过添加拟合函数，该模型能够提供可接受的吻合度（在10 nA cm−2范围内），模拟与实验得到的a-Si:H衬底的漏电流密度。对12 μm厚器件进行的额外瞬态模拟，以模拟其对实验数据的响应，与文献中找到的实验数据在所需操作电压以耗尽厚a-Si:H器件方面表现出卓越的吻合度（1%）。本研究中开发的a-Si:H模型提供了一种优化基于a-Si:H的粒子检测应用器件的方法。