A Microstructual Analysis of Au/Pd/Ti Ohmic Contacts for GaAs-Based Heterojunction Bipolar Transistors (HJBTs)
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ABSTRACTAu/Pd/Ti and Au/Ti/Pd ohmic structures to thin p+-GaAs layers have been investigated for use as contacts to the base region of HJBTs. The Au/Pd/Ti contact system yielded specific contact resistivities at or above 2.8 × 10−5Ω:cm2. Heat treatments up to 8 minutes at 380°C caused only limited interaction between the metallization and the semiconductor. The metal penetrated to a maximum depth of ≃2nm. Specific contact resistivity values less than 10−5Ωcm2 were achieved using the Au/Ti/Pd (400/75/75nm) scheme. The nonalloyed Au/Ti/Pd contact showed the best combination of electrical and structural properties with a contact resistivity value of 9 × 10≃6Ωcm2 and Pd penetration of the GaAs epilayer to a depth of cs30nm.
2014 ◽
Vol 17
(4)
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pp. 394-397
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1997 ◽
Vol 12
(9)
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pp. 2249-2254
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2019 ◽
Vol 58
(SH)
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pp. SHHD01
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2020 ◽
Vol 67
(4)
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pp. 1726-1729
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