2016 13th China International Forum on Solid State Lighting: International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS)最新文献

{"title":"Effect of Gan interlayer thickness on the Algan/Gan heterostructure field-effect transistors for self-terminated wet etching process","authors":"Liuan Li, Liang He, Fan Yang, Zijun Chen, Xiaorong Zhang, Lei He, Zhisheng Wu, Baijun Zhang, Yang Liu","doi":"10.1109/IFWS.2016.7803759","DOIUrl":"https://doi.org/10.1109/IFWS.2016.7803759","url":null,"abstract":"In this paper, we investigated the effect of GaN interlayer thickness and AlGaN back barrier layer on the material and electrical properties of AlGaN/GaN HFETs. When the thickness of GaN interlayer is approximately 3 and 5 nm, it will slightly increase surface roughness and degrades 2DEG carrier density. The 2DEG channel is also up shifted to nearly beneath the GaN interlayer. By contrast, 10 nm GaN interlayer causes a clear double channel and an obvious degradation of 2DEG carrier density. It is also demonstrated that the introduction of AlGaN back barrier layer can effectively improve the 2DEG confinement and reduce the scattering, resulting in smaller frequency dispersion effect. HFETs fabricated on the sample with both back barrier layer and 5 nm GaN interlayer present good pinch-off characteristics and high on/off ratio of approximately 107. This optimized structure is suitable for application in self-terminated wet etching process.","PeriodicalId":331453,"journal":{"name":"2016 13th China International Forum on Solid State Lighting: International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS)","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126116268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of AlN buffer on the properties of AlN films grown on sapphire substrate by MOCVD","authors":"Xiang Chen, Yun Zhang, Jianchang Yan, Yanan Guo, Shuo Zhang, Junxi Wang, Jinmin Li","doi":"10.1109/IFWS.2016.7803774","DOIUrl":"https://doi.org/10.1109/IFWS.2016.7803774","url":null,"abstract":"We presented a study on the effects of low-temperature (LT) AlN buffer growth time and surface morphology on the properties of high-temperature (HT) AlN epitaxial films using metal-organic chemical vapor deposition. Atomic force microscopy, Double crystal X-ray diffraction, Raman test and optical transmission measurement were employed to characterize the four HT AlN samples with different LT AlN buffer growth time. The results demonstrate that the LT AlN buffer growth time and surface morphology are key parameters for the quality of the HT AlN films. With an optimized LT AlN buffer growth time of 6 minutes, a 1-μm-thick high-quality and crack-free AlN film was obtained. The full width at half-maximum of X-ray diffraction (0002) and (1012) rocking curves of the AlN film are 42 and 530 arcsec, respectively. The AFM measurement shows an atomically flat surface with a root mean square roughness of 0.149 nm and a step-flow growth mode. The transmittance spectrum presents a sharp absorption band gap at wavelength 203 nm.","PeriodicalId":331453,"journal":{"name":"2016 13th China International Forum on Solid State Lighting: International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS)","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126181978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel designs of 4H-SiC trench gate metal-oxide-semiconductor field effect transistors (UMOSFETs) with low on-resistance","authors":"Kai Tian, Jindou Liu, Jing Cui, Chuangji Zhou, Anping Zhang","doi":"10.1109/IFWS.2016.7803750","DOIUrl":"https://doi.org/10.1109/IFWS.2016.7803750","url":null,"abstract":"In this paper novel 4H-SiC UMOSFETs structures with n-type wrapping region and superjunctions are proposed to reduce on-resistance while maintaining breakdown voltage. In the proposed 4H-SiC UMOSFETs structure an n-type region is created to wrap the p+ shielding region at the bottom of the trench gate. The on-resistances of the optimized 4H-SiC UMOSFETs and the conventional one are 2.31mΩ-cm² and 3.56 mΩ-cm² at V<inf>GS</inf>=15 V and V<inf>DS</inf>=10 V respectively. The on-resistance and the FOM (figure of merit = VBR²/Ron) improve by 35.1% and 37.3% respectively. By introducing a current spreading layer (CSL)the on-resistance of the optimized 4H-SiC UMOSFETs with superjunctions is 6.03mΩ-cm² compared with 17.36 mΩ-cm² for the conventional structure. The FOM of the optimized device with CSL is improved by 110.4% compared with the conventional one with same doping concentration.","PeriodicalId":331453,"journal":{"name":"2016 13th China International Forum on Solid State Lighting: International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS)","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114775043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Normally-off recessed MOS-gate AlGaN/GaN HEMTs with over +4V saturation drain current density and a 400V breakdown voltage","authors":"Cheng Zhe, Zhang Yun, Zhang Lian, Zhao Yong-Bing, Wang Jun-Xi, Liao Jin-min","doi":"10.1109/IFWS.2016.7803760","DOIUrl":"https://doi.org/10.1109/IFWS.2016.7803760","url":null,"abstract":"Owing to outstanding properties of two-dimensional electron gas (2DEG) and GaN-base material, such as high electron mobility and high critical electric field, AlGaN/GaN high electron mobility transistors (HEMTs) have been considered as the next-generation power semiconductor devices with high power conversion efficiency, high switching frequency and high-temperature operation capability. For power switching applications, enhancement mode (e-mode, or say normally-off) transistors are desired for fail-safe operation and silicon-compatible gate drive circuit. However, e-mode operation is difficult for AlGaN/GaN-based HEMTs because of the natural existence of 2DEG. To achieve e-mode operation, several approaches have been reported, including gate recess structure, fluorine plasma ion implantation, p-type gate structure and selective channel regrowth, etc. This paper reports normally-off AlGaN/GaN HEMTs with a recessed MOS-gate. After mesa isolation and Source and drain metal, the gate recess process used inductively coupled plasma (ICP). In order to avoid severe etching damage and obtain high drain current density, etching power was carefully optimized. The etching rate is slow for accurate etching depth control to leverage the current density and threshold voltage. After that, an O2 plasma treatment was applied using a plasma asher to oxidize the damaged semiconductor surface. The oxide layer was then removed in HCl: DI-water (1: 3). The next step is an atomic layer deposition (ALD) of Al2O3 as the gate dielectric to increase the breakdown voltage. Follow after that, gate metal and pad metal. By the process, our team made three kinds of HEMTs with different recessed gate depths. The first one, which has been report before, exhibits a high threshold voltage of +4.6V, a specific on-resistance of 4mΩ-cm⁁2 and a drain current density of 108 mA/mm. This paper will show the others fabricated in the later researches. The device transfer curves show that this normally-off recessed MOS-gate AlGaN/GaN HEMTs exhibit threshold voltage of +0.9V and +2.1V, respectively. Additionally, the specific on-resistance and saturation drain current density of the device with 0.9V threshold voltage are 2.26mΩ-cm⁁2 and 326mA/mm, while 2.1V-Threshold Voltage-device are 3.03mΩcm⁁2 and 173mA/mm. Both of the two HEMTs have a breakdown voltage over 400V.","PeriodicalId":331453,"journal":{"name":"2016 13th China International Forum on Solid State Lighting: International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125355565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Over 10 kV vertical GaN p-n junction diodes with high-K/low-K compound dielectric structure","authors":"Jiangfeng Du, Zhenchao Li, Dong Liu, Zhiyuan Bai, Qi Yu","doi":"10.1109/IFWS.2016.7803756","DOIUrl":"https://doi.org/10.1109/IFWS.2016.7803756","url":null,"abstract":"In this letter, a vertical GaN p-n junction diode with high-K/low-K compound dielectric structure (GaN CD-VGD) is proposed. The high-K/low-K compound dielectric structure consists of a layer of high dielectric constant and multilayer dielectric layers which have a lower dielectric constant, and these compound dielectric layers formed along the current flow direction. Compared with a conventional p-n diode, the edge electric field will be suppressed due to the effects of high-K passivation. And a new electric field peak will be introduced in the p-n diodes, because of a discontinuity of electrical field at the interface of high-K and low-K layer. Therefore the distribution of electric field in p-n diodes will become more uniform and an enhancement of breakdown voltage can be achieved. A best trade-off breakdown voltage (BV) and on-resistance (Ron) have been obtained by optimizing device parameters including dielectric layer situation, length and width. Numerical simulation demonstrate that GaN CD-VGD with a BV of 10650V and a Ron of 5.83 mΩ-cm2, resulting in a figure-of-merit (VB2/Ron) of 19 GW/cm2.","PeriodicalId":331453,"journal":{"name":"2016 13th China International Forum on Solid State Lighting: International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122181530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancement-mode Al2O3/InAlGaN/GaN MOS-HEMTs with a record drain current density of 1.7 A/mm and a threshold voltage of +1.5 V","authors":"Kai Zhang, Jianjun Zhou, C. Kong, Y. Kong, Tangsheng Chen","doi":"10.1109/IFWS.2016.7803758","DOIUrl":"https://doi.org/10.1109/IFWS.2016.7803758","url":null,"abstract":"The paper reports high performance enhancement-mode MOS-HEMT based on quaternary InAlGaN barrier. A self-aligned gate technology is used for gate recessing, dielectric deposition and gate electrode formation processes, where improved digital recessing process as well as O2 plasma-assisted Al2O3 gate dielectric is developed. Fabricated E-mode MOS-HEMT delivers a record output current density of 1.7A/mm with a threshold voltage (VTH) of 1.5 V, and a small on-resistance (Ron) of 2.0 Q-mm. Excellent VTH hysteresis and greatly improved gate leakage characteristics are also demonstrated.","PeriodicalId":331453,"journal":{"name":"2016 13th China International Forum on Solid State Lighting: International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123581178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electrical-thermo-mechanical Simulation for aluminum wire bonds in SiC Schottky diode packages","authors":"Changqing Bai, Jiajie Fan, C. Qian, W. Guo, Xuejun Fan, Guoqi Zhang","doi":"10.1109/IFWS.2016.7803744","DOIUrl":"https://doi.org/10.1109/IFWS.2016.7803744","url":null,"abstract":"Compared to traditional silicon based semiconductors, wide band gap semiconductors (e.g. GaN and SiC) have been widely used in high power electronics with their advantages of higher thermal conductivity, higher breakdown field strength, higher operating temperature and lower power loss. The SiC power diode packages, including Schottky Barrier Diode (SBD) and Junction Barrier Schottky (JBS), are usually manufactured with the SiC die as a function chip and aluminum wires as interconnections. Since aluminum wires are usually operated under the condition of high temperature and high power cycling, their fatigue damage is considered as one of great failures happened in package level. Because of the mismatch of coefficient of thermal expansions (CTEs) between the interconnections, aluminum wires are highly stressed under a multiple electrical-thermo-mechanical condition. This paper assesses the reliability of wire bonds in a SiC SBD package under an accelerated operation test condition with higher currents. And the fatigue damage of the wire bond was predicted by using a multi-physics finite element (FE) simulation method. In details, the strain-based and stress-based 3D finite element simulation models, which will be afforded to the traditional strain-based Coffin-Manson model and stress-based Basquin's equation for fatigue life prediction, were chosen to simulate the stress/strain density distribution of the wire bond in the SiC SBD package. Finally, the effects of the high current conditions on the the stress/strain density distribution of the wire bond were analyzed based on the simulation results.","PeriodicalId":331453,"journal":{"name":"2016 13th China International Forum on Solid State Lighting: International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131928734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimized P-emitter doping for switching-off loss of superjunction 4H-SiC IGBTs","authors":"Zhanwei Shen, Feng Zhang, Lixin Tian, Guoguo Yan, Zhengxin Wen, Wanshun Zhao, Lei Wang, Xingfang Liu, Guosheng Sun, Yiping Zeng","doi":"10.1109/IFWS.2016.7803742","DOIUrl":"https://doi.org/10.1109/IFWS.2016.7803742","url":null,"abstract":"This paper studied the effect of P-emitter concentration on the turn-off power loss (Eoff) of superjunction 4H-SiC IGBTs (SJ IGBTs) via simulation. Two types of SJ IGBTs, with blocking voltages being 2.0 kV, and 5.5 kV respectively, were studied at various temperatures from 300 K to 500 K. It was found that two kinds of minimum Eoff, Eoff, min, emerged due to the differences of conductivity modulation in the pillar regions and the roles of the parasitic PNP transistor. For the 2 kV-class SJ IGBT, the concentration of excess carrier in the drift layer was varied with a peak value at moderate P-emitter doping level. And there was a catenary temperature dependence between EoJJ and P-emitter doping concentration owing to the interaction of hole and electron current. While for the 5.5 kV-class, the manifestation of Eoff, min emerged when higher degree of conductivity modulation occurred in the drift layer. And Eoff, min turned to appearing at high p-emitter doping level for lower operating temperature. Also the temperature-dependent fluctuation of Eoff for the 5.5 kV-class went up at high P-emitter doping concentration. These results can be valuable for the reference design rules of novel 4H-SiC SJ IGBTs and bring further improvement for the static and dynamic performances of devices.","PeriodicalId":331453,"journal":{"name":"2016 13th China International Forum on Solid State Lighting: International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115885403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and fabrication of 1.2kV 4H-SiC DMOSFET","authors":"Run-Hua Huang, Y. Tao, S. Bai, Gang Chen, Ling Wang, Rui Li, Yun Li, Zhifei Zhao","doi":"10.1109/IFWS.2016.7803745","DOIUrl":"https://doi.org/10.1109/IFWS.2016.7803745","url":null,"abstract":"A 4H-SiC MOSFET with breakdown voltage higher than 1200V has been successfully designed and fabricated. Numerical simulations have been performed to optimize the parameters of DMOSFET. The n-type epilayer is 10 μm thick with a doping of 6×10¹⁵ cm⁻³. The devices were fabricated with a floating guard ring edge termination. The drain current Id = 10 A at Vg = 20 V, corresponding to Vd = 2.0 V.","PeriodicalId":331453,"journal":{"name":"2016 13th China International Forum on Solid State Lighting: International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123751186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The breakdown behavior of GaN epitaxial material on silicon","authors":"Jialin Zhang, Liang He, Liuan Li, Fan Yang, Zhen Shen, D. Zhou, Zijun Chen, Xiaorong Zhang, Lei He, Zhisheng Wu, Baijun Zhang, Yang Liu","doi":"10.1109/IFWS.2016.7803762","DOIUrl":"https://doi.org/10.1109/IFWS.2016.7803762","url":null,"abstract":"In this paper, the leakage path and breakdown behavior of GaN on silicon substrate were studied systematically. Three terminal breakdown voltage characteristics of the samples with various ohmic contacts spacing were evaluated. With increasing the spacing between the contacts, the breakdown voltage increased linearly first and then saturated. In order to clarify the breakdown behavior, leakage path after breakdown test was further analyzed and the breakdown behaviors were identified. Furthermore, the burnt buffer layer was observed by FIB SEM after device breakdown intuitively. It manifested that the spacing dependent breakdown characteristics of the epitaxial layer was ascribe to that different leakage paths dominated the breakdown at different spacing.","PeriodicalId":331453,"journal":{"name":"2016 13th China International Forum on Solid State Lighting: International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131355683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}