標題: New Cu/Mo/Ge/Pd ohmic contacts on highly doped n-GaAs for InGaP/GaAs heterojunction bipolar transistors
作者: Chang, Chun-Wei
Hseh, Tung-Ling
Chang, Edward Yi
材料科學與工程學系
Department of Materials Science and Engineering
關鍵字: copper metallization;GaAs;heterojunction bipolar transistor;ohmic contact;Pd/Ge
公開日期: 1-Dec-2006
摘要: The feasibility of using novel Cu/Mo/Ge/Pd ohmic contacts on n+-GaAs for heterojunction bipolar transistors (HBTs) is investigated. The electrical and material characteristics of the Cu/Mo/Ge/Pd/n(+)-GaAs structure were studied. After thermal annealing at 350 degrees C, the specific contact resistances of the copper ohmic contacts Cu/Mo/Ge/Pd were measured to be 2.8 x 10(-7) Omega cm(2). Judging from the data of sheet resistance, X-ray diffraction analysis, Auger electron spectroscopy, and transmission electron microscopy, the Cu/Mo/Ge/Pd contact structure was very stable after annealing at 350 degrees C. However, after 400 degrees C annealing, the reaction of copper with the underneath layers started to occur and formed MoGe2, Cu3Ga and Ge3CU phases. An InGaP/GaAs HBT with C'u/Mo/Ge/Pd contact metals was fabricated and compared with an HBT fabricated with traditional Au/Ni/Ge/Au contact metals. These two kinds of HBTs showed similar device characteristics. After reaching thermal stability and per-forming a high current-accelerated stress test at a current density of 120 kA/cm(2) for 24h, the device with the Cu/Mo/Ge/Pd ohmic contacts still exhibits excellent electrical characteristics.
URI: http://dx.doi.org/10.1143/JJAP.45.9029
http://hdl.handle.net/11536/11505
ISSN: 0021-4922
DOI: 10.1143/JJAP.45.9029
期刊: JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS
Volume: 45
Issue: 12
起始頁: 9029
結束頁: 9032
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