利用高K绝缘介质的新型功率半导体器件的研究

发布时间：2018-06-12 10:28

本文选题：功率半导体器件 + 超结　；参考：《电子科技大学》2016年博士论文

【摘要】：随着经济的发展,全球对电能的需求量在逐年增加。如今,中国已超越美国成为了世界上电能消耗量最大的国家,而且中国的电能消耗量的增长率也远超美国和欧盟。这样的发展趋势显然是我国实现节能减排目标的一个重大挑战。面对这一挑战,高效地利用电能显得尤为重要。电力电子技术是一种能将电能高效利用的新兴技术,而功率半导体器件是电力电子技术的核心。因此,研究功率半导体器件对我国实现节能减排有重要意义。电子科技大学陈星弼教授提出的超结(Superjunction,SJ)耐压层是功率半导体器件领域的重要发明。SJ耐压层可以获得远比传统耐压层更优异的比导通电阻(Ron)与击穿电压(VB)的关系,因而被誉为功率半导体器件的里程碑。然而,SJ耐压层也有一些缺点,比如VB容易受电荷非平衡条件的影响等。为此,陈星弼教授又提出了高K耐压层。高K耐压层不仅改善了SJ耐压层的一些缺点,而且可以获得与SJ耐压层相近的Ron与VB的关系。作者在陈星弼教授的指导下主要开展了应用高K耐压层的纵向双扩散金属-氧化物-半导体场效应晶体管(VDMOS)和肖特基二极管(SBD)的研究。本文中主要的创新工作有:1.为了深入理解高K耐压层的原理及特点,给出了高K耐压层的解析模型,解释了高K耐压层的基本原理,并给出了高K耐压层的最优化设计方法以及最优化的Ron与VB的关系。仿真结果显示,在相同VB下,与应用了SJ耐压层的VDMOS(SJ-MOSFET)相比,应用了高K耐压层的VDMOS(Hk-MOSFET)的Ron会稍大一点,开关时间会更长一些,但在大电流下的耐压会明显更高。此外,还提出了适用于Hk-MOSFET的叉指条形元胞和两种六角形元胞的统一的简化设计方法,并比较了这些元胞结构的Ron。理论和仿真计算均发现,若要获得最小的Ron,就需要根据设计条件来选取合适的元胞结构。2.研究了一种改进的Hk-MOSFET,给出了适用于改进的Hk-MOSFET的解析模型以及最优化设计的方法,并与以前的Hk-MOSFET以及SJ-MOSFET作了对比。理论和仿真计算结果均显示,在相同VB下,改进的Hk-MOSFET的Ron比以前的Hk-MOSFET的Ron低30%~50%。一个VB=600 V的例子的仿真结果显示,改进的Hk-MOSFET的功率优值(Figure of Merit,FOM=VB2/Ron)达到了31.8 MW/cm2,它比以前的Hk-MOSFET的FOM高73%,也比SJ-MOSFET的FOM高57%。另外,与SJ-MOSFET相比,这两种Hk-MOSFET的VB受工艺误差的影响也都明显更小。3.研究了一种利用高K绝缘介质的SJ耐压层(Hk-SJ耐压层),提出了一个解析模型用于优化设计该结构,并将应用了Hk-SJ耐压层的VDMOS(Hk-SJ-MOSFET)与传统SJ-MOSFET作了对比。解析模型中的VB的目标设计值与仿真结果很接近,两者之间误差仅为-5%到+8%。此外,在高K绝缘介质的介电系数?I=20~300?0下,Hk-SJ-MOSFET的最优化的Ron几乎不变。在相同的VB和元胞尺寸下,Hk-SJ-MOSFET的Ron比传统SJ-MOSFET的Ron低约8%~20%。VB=400 V和VB=800 V的两个例子的仿真结果均显示,当?I达到60?0时,Hk-SJ-MOSFET中p区的掺杂浓度误差对VB的影响可以比传统SJ-MOSFET中p区的掺杂浓度误差对VB的影响小2倍。4.研究了几种应用了高K耐压层的SBD(Hk-SBD),并将它们与应用了SJ耐压层的SBD(SJ-SBD)作了对比。仿真结果显示,Hk-SBD的Ron和VB的值与SJ-SBD的Ron和VB的值相接近,而且Hk-SBD的反向恢复特性比SJ-SBD的反向恢复特性更软。为了降低Hk-SBD的反向漏电流并且不增加Ron,还提出了一种Hk-SBD的新结构,即带有n+-poly的Hk-SBD。该结构中引入的n+-poly区不仅在在反向承受高压时可以降低肖特基结上的电场,而且在正向导通时在n区顶部区域与高K绝缘体区界面上可以形成一个高浓度的电子积累层。一个VB=400 V的例子的仿真结果显示,与以前的Hk-SBD相比,带有n+-poly的Hk-SBD在350 V反向偏压下的漏电流降低了约40倍,而比导通电阻(等于3.13 mΩ?cm2)几乎不变。
[Abstract]:With the development of the economy, the demand for electric energy is increasing year by year. Now, China has surpassed the United States and became the largest country in the world, and the growth rate of electricity consumption is far beyond the United States and the European Union. This trend is obviously a major challenge for our country to realize the goal of energy saving and emission reduction. It is very important to make use of electric energy efficiently. Power electronics is a new technology which can make use of electric energy efficiently. Power semiconductor devices are the core of power electronics. Therefore, it is important to study power semiconductor devices for energy saving and emission reduction in China. Professor Chen Xingbi of the University of electronic science and technology Superjunction (SJ) pressure resistant layer is an important invention in the field of power semiconductor devices. The.SJ pressure resistance layer can obtain much better relationship between the specific resistance (Ron) and the breakdown voltage (VB), which is far superior to the traditional pressure layer. Therefore, it is known as the milestone of the power semiconductor device. However, the SJ resistance layer also has some disadvantages, such as the VB is easily affected by the charge imbalance. To this end, Professor Chen Xingbi also proposed a high K pressure layer. The high K pressure layer not only improved some shortcomings of the SJ pressure resistance layer, but also obtained the relationship between the Ron and the VB, which was similar to the SJ pressure resistance layer. Under the guidance of Professor Chen Xingbi, the longitudinal double diffusion metal oxide semiconductor field with high K pressure resistance layer was mainly carried out. The study of effect transistors (VDMOS) and Schottky diode (SBD). The main innovations in this paper are as follows: 1. in order to understand the principle and characteristics of high K pressure resistance layer, the analytical model of high K pressure resistance layer is given, the basic principle of high K pressure layer is explained, and the optimal design method of high K pressure resistant layer and the optimal Ron and VB are given. The simulation results show that, under the same VB, the Ron of the VDMOS (Hk-MOSFET) with the high K pressure layer is slightly larger than the VDMOS (SJ-MOSFET) with the application of the SJ pressure layer, and the switching time will be longer, but the pressure in the high current will be significantly higher. Furthermore, the interdigital cell and two kinds of six angles for Hk-MOSFET are also proposed. The unified simplified design method of cell cells, and comparing the Ron. theory and simulation calculation of these cellular structures, it is found that if we want to get the smallest Ron, we need to select the appropriate cellular structure.2. according to the design conditions and study an improved Hk-MOSFET, and give the analytical model and optimal design for the improved Hk-MOSFET. The method is compared with the previous Hk-MOSFET and SJ-MOSFET. Both theoretical and simulation results show that, under the same VB, the simulation results of the improved Hk-MOSFET Ron as compared to the previous Hk-MOSFET Ron low 30%~50%. one VB=600 V show that the improved Hk-MOSFET work rate is 31.8 /cm2, which is 73% higher than the FOM of previous Hk-MOSFET, and 57%. higher than SJ-MOSFET's FOM. Compared with SJ-MOSFET, the VB of the two Hk-MOSFET is significantly smaller than that of the process error..3. studies a SJ withstand layer using a highly K insulating medium. An analytical model is proposed for the optimization of the structure and will be applied. The VDMOS (Hk-SJ-MOSFET) of the Hk-SJ pressure layer is compared with the traditional SJ-MOSFET. The target design value of the VB in the analytical model is close to the simulation result, and the error between the two is only -5% to +8%.. Under the dielectric coefficient of the high K dielectric, I=20~300? 0, the optimal Ron of Hk-SJ-MOSFET is almost invariable. Under the same VB and cell size, The simulation results of two examples of Hk-SJ-MOSFET's Ron compared to the traditional SJ-MOSFET Ron low 8%~20%.VB=400 V and VB=800 V show that when the I reaches 60? 0, the doping concentration error in p zone in Hk-SJ-MOSFET is 2 times smaller than the influence of the doping concentration error in the traditional region. The SBD (Hk-SBD) of the layer is compared with the SBD (SJ-SBD) applied to the SJ pressure layer (SJ-SBD). The simulation results show that the values of the Ron and VB of the Hk-SBD are close to the Ron and VB values of SJ-SBD, and the reverse recovery characteristic of the Hk-SBD is more soft than the reverse recovery characteristic. The new structure of Hk-SBD, that is, the n+-poly Zone introduced in the Hk-SBD. with the n+-poly, can not only reduce the electric field on the Schottky junction in the reverse high pressure, but also form a high concentration of electron accumulation layer at the top of the N region and the high K insulator interface in the forward conduction. A simulation of an example of VB=400 V. The results show that the leakage current of the Hk-SBD with n+-poly in the 350 V reverse bias is approximately 40 times lower than that of the previous Hk-SBD, while the specific resistance (equal to 3.13 m Omega cm2) is almost invariable.
【学位授予单位】：电子科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN386;TN311.7

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