Pd/p-GaN欧姆接触退化机理

张帆; 王荣新; 黄思溢; 田爱琴; 刘建平; 杨辉

doi:10.37188/CJL.20210092

您当前的位置：

首页 >

文章列表页 >

Pd/p-GaN欧姆接触退化机理

发光产业及技术前沿 | 更新时间：2021-07-22

- Pd/p-GaN欧姆接触退化机理
- Degradation Mechanism of Pd/p-GaN Ohmic Contacts
- 发光学报 2021年42卷第7期页码：1065-1073
- 作者机构：
  
  1.中国科学院苏州纳米技术与纳米仿生研究所　纳米器件与相关材料研究部，江苏　苏州　 215123
  2.上海科技大学　物质科学与技术学院，上海　 201210
  3.中国科学院苏州纳米技术与纳米仿生研究所　纳米真空互联实验平台，江苏　苏州　 215123
- 作者简介：
  
  [ "张帆(1994-)，男，山西太原人，硕士研究生，2017年于中北大学获得学士学位，主要从事GaN半导体蓝绿光激光器的研究。E-mail: fzhang2019@sinano.ac.cn" ]
  [ "王荣新(1963-)，女，河北石家庄人，博士，正高级工程师，2005年于中国香港大学获得博士学位，主要从事微纳加工工艺、半导体器件的制备和表征研究。E-mail:rxwang2008@sinano.ac.cn" ]
  [ "杨辉(1961-)，男，天津人，博士，研究员，1991年于中国科学院半导体研究所获得博士学位，主要从事Ⅲ-Ⅴ族化合物半导体的材料生长、物理分析及器件的研究。E-mail:hyang2006@sinano.ac.cn" ]
- 基金信息：
  
  国家自然科学基金(11974378;61834008;61574160;61804164;61704184);国家重点研究发展计划(2017YFE0131500;2017YFB0405000;2017YFB0403101);江苏省自然科学基金(BK20180254)
- DOI：10.37188/CJL.20210092
  中图分类号： O482.31
- 纸质出版日期：2021-07-01，
  
  收稿日期：2021-03-16，
  
  修回日期：2021-04-04，
扫描看全文
张帆, 王荣新, 黄思溢, 等. Pd/p-GaN欧姆接触退化机理[J]. 发光学报, 2021,42(7):1065-1073.

Fan ZHANG, Rong-xin WANG, Si-yi HUANG, et al. Degradation Mechanism of Pd/p-GaN Ohmic Contacts[J]. Chinese Journal of Luminescence, 2021,42(7):1065-1073.
张帆, 王荣新, 黄思溢, 等. Pd/p-GaN欧姆接触退化机理[J]. 发光学报, 2021,42(7):1065-1073. DOI： 10.37188/CJL.20210092.

Fan ZHANG, Rong-xin WANG, Si-yi HUANG, et al. Degradation Mechanism of Pd/p-GaN Ohmic Contacts[J]. Chinese Journal of Luminescence, 2021,42(7):1065-1073. DOI： 10.37188/CJL.20210092.

摘要

近几年，Ⅲ-Ⅴ族半导体GaN由于其宽直接带隙，在高温、高功率器件方面得到了广泛研究。但是，目前GaN器件的性能依然受到了p型欧姆接触性能不良的限制，在长期使用过程或高温环境中激光器等器件性能退化严重。因此，获得性能优异的p-GaN接触仍然是一个巨大的挑战。虽然Pd基的金属体系已然在p-GaN获得了欧姆接触，但是Pd与GaN接触之后的微观结构及其高温特性尚不为人知。本文针对常用于p型GaN接触的第一层金属Pd材料，讨论了Pd/p-GaN接触界面的特性和退化机制。通过四探针测试仪、X射线光电子能谱(XPS)和原子力显微镜(AFM)实验测试和分析对比，发现Pd/p-GaN界面受到氧气和温度影响的退化过程。高温退火在界面处促成Ga-Pd合金相生成利于形成良好的接触，但是在有氧参与的情况下，金属的氧化反应超越其他因素成为主导，致使界面和性能发生明显的退化。温度越高退化越严重，甚至表面形貌状态完全改变，由平滑的原子台阶形貌转化呈现出树枝状晶粒状态。因此，保持Pd与p-GaN界面清洁、控制界面的氧成分不仅是形成合金态获得良好接触的关键，而且也关系着器件的长期稳定和可靠，是防止器件性能衰减和退化要害所在。

Abstract

GaN-based wide bandgap semiconductors and devices have been quickly emerging as a new frontier and cutting-edge technique. It is necessary to fabricate Ohmic contact for GaN device application. Pd is one of candidate metals for fabricating metal/p-GaN Ohmic contacts. Under the identical preparation conditions

different thickness Pd films were sputtered on p-GaN epilayers in sputtering chamber directly connected with MOCVD growth system. After the metal deposition

the samples were then annealed at 300 ℃ and 600 ℃ in ambient atmosphere of N

∶O

=4∶1 or under vacuum conditions for 90 s. They were measured and characterized by four-probe Van de Pauw

X-ray photoelectron spectroscopy(XPS)

and atomic force microscopy(AFM). It is found that the electrical properties and surface morphologies of samples were dependent on annealing ambient atmosphere and heat treatment temperature conditions. When the samples were annealed at 600 ℃ under high vacuum conditions

Ga can be diffused out from Pd/p-GaN interface. It would be helpful to make Ga and Pd reactive to become alloy as well as to produce Ga vacancy for Ohmic contact. While the samples were annealed in N

∶O

=4∶1 environment

however

oxidation of metal Pd and Ga becomes a dominant factor resulting in degradation of the Ohmic contacts.The higher the annealing temperature in oxygen environment

the worse the electrical properties. Surface morphologies of the annealed samples were completely changed from a smooth atomic step morphology to a dendritic polycrystal grain state if oxygen was participated into the interface during the annealing process. Therefore

avoiding oxygen incorporation at Pd/p-GaN interface shall be a key role in forming alloy and Ohmic contact

which favors the stability and reliability of device performance.

关键词

p型GaN欧姆接触XPS界面

Keywords

p-GaNOhmic contactXPSinterface

references

WU Y, CHEN C Y, DEL ALAMO J A. Electrical and structural degradation of GaN high electron mobility transistors under high-power and high-temperature direct current stress [J].J. Appl. Phys., 2015, 117(2): 025707-1-6.

SAADAT O I, CHUNG J W, PINER E L, et al. Gate-first AlGaN/GaN HEMT technology for high-frequency applications [J].IEEE Electron Device Lett., 2009, 30(12): 1254-1256.

KHAN A K, ALIM M A, GAQUIERE C. 2DEG transport properties over temperature for AlGaN/GaN HEMT and AlGaN/InGaN/GaN pHEMT [J].Microelectron. Eng., 2021, 238: 111508.

AHMAD S, RAUSHAN M A, SIDDIQUI M J. Achievements and perspectives of GaN based light emitting diodes:a critical review [C].2017 International Conference on Trends in Electronics and Informatics(ICEI), Tirunelveli, India, 2017:224-229.

NAKAMURA S, FASOL G. The Blue Laser Diode:GaN Based Light Emitters and Lasers[M].Berlin, Heidelberg: Springer, 2013.

SZE S M. Physics of Semiconductor Devices[M].New York: John Wiley & Sons, 1981.

RUVIMOV S, LILIENTAL-WEBER Z, WASHBURN J, et al. Microstructure of Ti/Al and Ti/Al/Ni/Au Ohmic contacts for n-GaN [J].Appl. Phys. Lett., 1996, 69(11): 1556-1558.

LUTHER B P, MOHNEY S E, JACKSON T N, et al. Investigation of the mechanism for Ohmic contact formation in Al and Ti/Al contacts to n-type GaN [J].Appl. Phys. Lett., 1997, 70(1): 57-59.

JACOBS B, KRAMER M C J C M, GELUK E J, et al. Optimisation of the Ti/Al/Ni/Au Ohmic contact on AlGaN/GaN FET structures [J].J. Cryst. Growth, 2002, 241(1-2): 15-18.

HO J K, JONG C S, CHIU C C, et al. Low-resistance Ohmic contacts to p-type GaN [J].Appl. Phys. Lett., 1999, 74(9): 1275-1277.

CHO H K, HOSSAIN T, BAE J W, et al. Characterization of Pd/Ni/Au Ohmic contacts on p-GaN [J].Solid-State Electron., 2005, 49(5): 774-778.

曾畅. GaN基激光器结构设计与关键工艺研究 [D].北京: 中国科学院研究生院, 2012.

ZENG C. Investigations on Device Structure and Key Processing of GaN-based Lased Diodes [D].Beijing: Graduate University of the Chinese Academy of Sciences, 2012. (in Chinese)

PAN C C, CHEN G T, HSU W J, et al. Thermal stability improvement by using Pd/NiO/Al/Ti/Au reflective Ohmic contacts to p-GaN for flip-chip ultraviolet light-emitting diodes [J].Appl. Phys. Lett., 2006, 88(6): 062113-1-3.

SPICER W E, LILIENTAL-WEBER Z, WEBER E, et al. The advanced unified defect model for Schottky barrier formation [J].J. Vac. Sci. Technol. B Microelectron. Process. Phenom., 1988, 6(4): 1245-1251.

KIM J K, LEE J L, LEE J W, et al. Low resistance Pd/Au Ohmic contacts to p-type GaN using surface treatment [J].Appl. Phys. Lett., 1998, 73(20): 2953-2955.

KUO C H, CHANG S J, SU Y K, et al. Low temperature activation of Mg-doped GaN in O2 ambient [J].Jpn. J. Appl. Phys., 2002, 41(2A): L112-L114.

ANDERSON T J, FEIGELSON B N, KUB F J, et al. Activation of Mg implanted in GaN by multicycle rapid thermal annealing [J].Electron. Lett., 2014, 50(3): 197-198.

GRODZICKI M, MAZUR P, ZUBER S, et al. Pd/GaN(0001) interface properties [J].Mater. Sci. -Poland, 2014, 32(2): 252-256.

WANG L, NATHAN M I, LIM T H, et al. High barrier height GaN Schottky diodes:Pt/GaN and Pd/GaN [J].Appl. Phys. Lett., 1996, 68(9): 1267-1269.

TREXLER J T, PEARTON S J, HOLLOWAY P H, et al. Comparison of Ni/Au, Pd/Au, and Cr/Au metallizations for Ohmic contacts to p-GaN [J].MRS Online Proc. Libr., 1996, 449(1): 1091-1096.

LIU Q Z, LAU S S. A review of the metal-GaN contact technology [J].Solid-State Electron., 1998, 42(5): 677-691.

TURA J M, REGULL P, VICTORI L, et al. XPS and IR(ATR) analysis of Pd oxide films obtained by electrochemical methods [J].Surf. Interface Anal., 1988, 11(8): 447-449.

BRUN M, BERTHET A, BERTOLINI J C. XPS, AES and Auger parameter of Pd and PdO [J].J. Electron Spectrosc. Relat. Phenom., 1999, 104(1-3): 55-60.

LI Z C, HUANG R, CHEN X, et al. The significant effect of carbon and oxygen contaminants at Pd/p-GaN interface on its Ohmic contact characteristics [J].Phys. Status Solidi (a), 2021, 218(4): 2000603.

HUANG R, LIU T, ZHAO Y F, et al. Angular dependent XPS study of surface band bending on Ga-polar n-GaN [J].Appl. Surf. Sci., 2018, 440: 637-642.

POWELL C J, JABLONSKI A. NIST electron inelastic-mean-free-path database 71, version 1.0[G].Gaithersburg, MD: National Institute of Standards and Technology, 1999.

TANUMA S, POWELL C J, PENN D R. Calculations of electron inelastic mean free paths. V. Data for 14 organic compounds over the 50-2 000 eV range [J].Surf. Interface Anal., 1994, 21(3): 165-176.

GARCÍA-TRENCO A, WHITE E R, REGOUTZ A, et al. Pd2Ga-based colloids as highly active catalysts for the hydrogenation of CO2 to methanol [J].ACS Catal., 2017, 7(2): 1186-1196.

GRODZICKI M, MAZUR P, PERS J, et al. Formation of GaPd2 and GaPd intermetallic compounds on GaN(0001) [J].Appl. Phys. A, 2015, 120(4): 1443-1451.

KRACKER M, WISNIEWSKI W, RÜSSEL C. Textures of Au, Pt and Pd/PdO nanoparticles thermally dewetted from thin metal layers on fused silica [J].RSC Adv., 2014, 4(89): 48135-48143.

ZEMLYANOV D, ASZALOS-KISS B, KLEIMENOV E, et al. In situ XPS study of Pd(111) oxidation. Part 1:2D oxide formation in 10-3 mbar O2 [J].Surf. Sci., 2006, 600(5): 983-994.

GABASCH H, UNTERBERGER W, HAYEK K, et al. In situ XPS study of Pd(111) oxidation at elevated pressure, Part 2:palladium oxidation in the 10-1 mbar range [J].Surf. Sci., 2006, 600(15): 2980-2989.

JANG H W, LEE J L. Mechanism for Ohmic contact formation of Ni/Ag contacts on p-type GaN [J].Appl. Phys. Lett., 2004, 85(24): 5920-5922.

WANG R X, TAO X M, WANG Y, et al. Microstructures and electrical conductance of silver nanocrystalline thin films on flexible polymer substrates [J].Surf. Coat. Technol., 2010, 204(8): 1206-1210.

KIM C C, KIM W H, JE J H, et al. Structural evolution of Pd/GaN (0001) films during postannealing [J].Electrochem. Solid-State Lett., 2000, 3(7): 335-337.

浏览量

107

下载量

CSCD

文章被引用时，请邮件提醒。

提交

工具集

关联资源

GaAs半导体表面的等离子氮钝化特性研究

多层Ti/Al电极结构对GaN/AlGaN HEMT欧姆接触特性的影响

有机电致发光器件的瞬态电响应特性

ITO/Rubrene表面及界面的AFM和XPS研究