本文選題：4H-SiC + SBD�。� 參考：《河北工業(yè)大學》2015年碩士論文

【摘要】：采用寬禁帶半導體材料4H-SiC制作的肖特基勢壘二極管SBD具有PN結二極管無法比擬的優(yōu)越特性。國外對4H-SiC材料及其器件的研制和分析已經(jīng)有了諸多報道,而國內(nèi)在這方面的研究起步較晚,研究成果的相關報道較少。因此開展4H-SiC SBD器件研究有重要的意義。在此背景下,本文對4H-SiC SBD器件的主要電學特性進行了系統(tǒng)研究,主要研究成果如下:1、為了解決由于4H-SiC SBD器件近表面的電場集邊效應造成的器件擊穿特性變差的問題,采用加入結終端結構的方法來降低器件近表面的強電場,提高器件的擊穿電壓。在掌握結終端結構分類的基礎上,確定采用延伸型終端結構來優(yōu)化4H-SiC SBD器件的反向擊穿特性。2、實現(xiàn)加入不同結終端結構的器件仿真。利用Silvaco TCAD軟件對器件進行仿真。首先仿真了加入兩級場限環(huán)結構的4H-SiC SBD器件,該結構的敏感參數(shù)有環(huán)間距、環(huán)的注入結深和環(huán)區(qū)摻雜濃度,仿真確定的最優(yōu)值環(huán)間距為3μm,結深為0.4μm,摻雜濃度為1×1017cm-3,環(huán)寬為10μm,此時器件的擊穿電壓為1200V。針對場限環(huán)結構對器件界面電荷很敏感的問題,在場限環(huán)結構基礎上,仿真了加入場板結構的器件特性,場板結構的敏感參數(shù)為場板長度,仿真確定其最優(yōu)值為20μm,此時器件的擊穿電壓可到達1350V。然后仿真了加入結終端擴展JTE結構的器件,該結構的敏感參數(shù)有JTE結構長度,注入結深和摻雜濃度,仿真確定其最優(yōu)值長度為30μm,結深為1.0μm,摻雜濃度為1×1018cm-3,在此情況下器件的擊穿電壓達到1500V。3、通過對比加入不同結終端結構器件的模擬仿真結果,可以看出與兩級場限環(huán)結構器件以及場限環(huán)和場板復合結構器件相比,加入JTE結構的器件擊穿特性更好。因此實驗制作了加入JTE結構的4H-SiC SBD器件。二次離子質(zhì)譜法SIMS測試得到實驗器件JTE結構區(qū)Al離子在0.9μm范圍內(nèi)的摻雜濃度為1018cm-3量級;Keithley4200半導體參數(shù)測試儀測試了器件的正反向電流-電壓特性曲線,得到器件在正向電流為0.7A時開啟電壓為0.9V,反向漏電流為10μA時擊穿電壓為1200V;從器件的反向恢復特性曲線可知器件的反向恢復時間僅為25ns。
[Abstract]:The Schottky barrier diode SBD made with wide band gap semiconductor material 4H-SiC has superior characteristics which can not be compared with PN junction diode. There have been many reports on the development and analysis of 4H-SiC materials and their devices abroad. The domestic research in this field is late and the related reports of the research results are less. Therefore, the 4H-SiC SBD device is carried out. In this context, the main electrical characteristics of 4H-SiC SBD devices are systematically studied in this paper. The main research results are as follows: 1, in order to solve the problem that the breakdown characteristics of the device caused by the edge effect of the electric field in the near surface of the 4H-SiC SBD device is poor, the method of joining the junction terminal structure is used to reduce the device. A strong electric field near the surface improves the breakdown voltage of the device. On the basis of the classification of the terminal structure, the extension type terminal structure is used to optimize the reverse breakdown characteristic of 4H-SiC SBD device, and the device simulation with different junction terminal structures is realized. The device is simulated with the Silvaco TCAD software. First, the simulation is added to the two stage. 4H-SiC SBD device with field limiting ring structure, the sensitive parameters of the structure are ring spacing, injection depth of ring and doping concentration in the ring region. The optimal ring spacing is 3 u m, the depth is 0.4 m, the doping concentration is 1 x 1017cm-3 and the ring width is 10 u m. At this time, the breakdown voltage of the device is 1200V. sensitive to the interface charge of the device. On the basis of the presence limit loop structure, the device characteristics added to the field plate structure are simulated. The sensitive parameter of the field plate structure is the field plate length. The simulation determines that the optimal value is 20 u m. At this time the breakdown voltage of the device can reach 1350V. and then simulates the device with the junction terminal to expand the JTE structure, and the sensitive parameter of the structure has the JTE structure length. With the injection depth and doping concentration, the optimum length is 30 mu m, the depth is 1 mu m and the doping concentration is 1 x 1018cm-3. Under this condition, the breakdown voltage of the device reaches 1500V.3. By comparing the simulation results of different junction terminal structure devices, it can be seen that it is combined with the field limiting ring structure and the field limit ring and the field plate. Compared with the structure device, the device with JTE structure has better breakdown characteristics. Therefore, the experiment made the 4H-SiC SBD device with the JTE structure. The two ion mass spectrometry SIMS test obtained the doping concentration of the Al ion in the JTE structure area of the experimental device in the range of 0.9 mu m, and the Keithley4200 semiconductor parameter tester tested the positive and negative of the device. To the current voltage characteristic curve, the breakdown voltage is 1200V when the positive current is 0.7A and the reverse leakage current is 10 A. The reverse recovery time of the device is only 25ns. from the reverse recovery characteristic curve of the device.
【學位授予單位】：河北工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN311.7
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本文編號：1906744