GaN基FP-HEMT器件的新结构与解析模型研究

发布时间：2018-04-13 05:11

本文选题：GaN基FP-HEMT + 正向击穿　；参考：《西安电子科技大学》2015年硕士论文

【摘要】：近年来,GaN基高电子迁移率晶体管(GaN基HEMT)以其优异特性,在大功率、高温、高频、抗辐照等应用领域中备受人们关注。而场板技术的引入,推动了GaN基HEMT的性能的更显著提高,为器件可满足当前更广泛的应用需求奠定了基础。场板可以提高GaN基HEMT器件的击穿电压、输出功率,并可改善器件的可靠性,然而,当前的众多现实问题,比如,高击穿场板器件结构的设计和工艺实现问题、高反向击穿场板器件结构的设计问题、复杂场板器件的优化设计问题等,仍然是国内外众多研究者们关注的焦点。本论文,针对上述关键问题开展了系统、深入的研究,主要的研究工作和成果如下:(1)提出了一种制造工艺简单且击穿电压高的T形栅场板GaN基HEMT器件,并基于数值仿真研究了该新型器件的沟道电场分布特点和规律。研究结果表明,相比传统的单层场板GaN基HEMT器件,T形栅场板可形成额外的沟道电场峰,从而可更有效地调制栅漏区域的电场分布,以改善器件正向击穿特性。(2)在改善GaN基HEMT器件反向阻断能力方面,提出了肖特基漏极多层漏场板HEMT器件和肖特基漏极复合场板GaN基HEMT器件两种新型器件,并对其工作机理进行了深入分析。研究结果表明,这两种结构均可以有效调节器件沟道电场分布,显著提高器件的反向击穿电压。在肖特基漏极多层漏场板GaN基HEMT器件中,可通过增加场板个数增加反向击穿电压,而在肖特基漏极复合场板GaN基HEMT器件中,通过增加浮空场板个数可以持续增加击穿电压,且该器件工艺实现相对更为简单。此外,本论文在对上述两类器件研究中,得到了众多具有实用价值的研究结果,这对于将来的器件实际工艺制作具有一定的参考意义。(3)基于泊松方程分别研究了传统栅场板HEMT器件和浮空栅场板HEMT器件的二维解析模型,模型中考虑了极化效应、耗尽区横向扩展、电容耦合等重要因素,基于所建解析模型详细分析了主要器件参数对沟道电势和沟道电场分布的影响,得到了具有实用价值的规律,最后采用Silvaco-TCAD数值仿真对所建模型进行了验证。研究结果表明,所构建的解析模型与数值仿真结果一致性较好,利用这些模型可以快速设计优化场板器件结构,分析器件工作物理机制。同时,这些模型的建模方法也可用于其他场板器件的建模中,具有很强的可移植性。
[Abstract]:In recent years, GaN-based high electron mobility transistors (GaN-based HEMTs) have attracted much attention in the applications of high power, high temperature, high frequency and radiation resistance due to their excellent properties.The introduction of field board technology promotes the performance of GaN based HEMT and lays the foundation for the device to meet the needs of more extensive applications.The field board can improve the breakdown voltage, output power and reliability of the GaN based HEMT device. However, there are many practical problems, such as the design of the high breakdown field board device structure and the implementation of the technology.Many researchers at home and abroad still pay close attention to the design of high reverse breakdown field board device structure and the optimization design of complex field board device.In this paper, a systematic and in-depth study is carried out on the key issues mentioned above. The main research work and results are as follows: 1) A simple and high breakdown voltage T gate GaN based HEMT device is proposed.Based on the numerical simulation, the characteristics and laws of the channel electric field distribution of the new device are studied.The results show that compared with the conventional single-layer GaN based HEMT devices, the T-shaped gate field plates can form additional channel electric field peaks, which can more effectively modulate the electric field distribution in the gate leakage region.In order to improve the forward breakdown characteristics of GaN HEMT devices, two new types of Schottky drain multilayer leakage field plate (HEMT) devices and Schottky drain composite GaN based HEMT devices are proposed in order to improve the reverse blocking capability of HEMT devices.The working mechanism is analyzed deeply.The results show that both of these structures can effectively adjust the channel electric field distribution of the device and significantly increase the reverse breakdown voltage of the device.In Schottky drain multilayer leakage field plate GaN based HEMT devices, the reverse breakdown voltage can be increased by increasing the number of field plates, while in Schottky drain composite field board GaN based HEMT devices, the breakdown voltage can be continuously increased by increasing the number of floating field plates.The process of the device is relatively simple.In addition, in the research of the two kinds of devices mentioned above, many practical results have been obtained in this paper.This has some reference significance for the practical fabrication of the device in the future. Based on Poisson equation, the two-dimensional analytical models of traditional gate field plate HEMT device and floating gate field plate HEMT device are studied respectively. Polarization effect is considered in the model.Based on the analytical model, the effects of main device parameters on channel potential and channel electric field distribution are analyzed in detail, and the law of practical value is obtained.Finally, the model is verified by Silvaco-TCAD numerical simulation.The results show that the analytical models are in good agreement with the numerical simulation results. Using these models, we can quickly design and optimize the structure of the field-plate devices and analyze the physical mechanism of the devices.At the same time, these modeling methods can also be used in the modeling of other field board devices, which has strong portability.
【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】：TN386

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