Metallurgical stability of ohmic contacts on thin baseInP/InGaAs/InP HBT's |
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| Authors: | Chor EF Malik RJ Hamm RA Ryan R |
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| Affiliation: | AT&T Bell Labs., Murray Hill, NJ; |
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| Abstract: | The metallurgical stability of ohmic contacts: Pt, Pt/Ti, Au/Ti, Au/Pt/Ti, and Au/Pt/Ti/W, on a 500 Å thick p+-InGaAs base of InP/InGaAs/InP HBTs have been investigated as a function of anneal temperature. All contacts were stable after a 300°C-30 s anneal. Pt contact failed at 350°C whereas Pt/Ti, Au/Ti, and Au/Pt/Ti contacts failed at 400°C. The failure mechanism was a collector leakage short owing to the penetration of Pt or Ti through the thin base. Only HBTs with Au/Pt/Ti/W contact were still functional after a 400°C anneal with no apparent shift in the turn-on voltage for the emitter and collector junctions |
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