Fabrication and Characteristics of Cu-metallized InGaP/GaAs HBT
碩士 === 國立交通大學 === 工學院半導體材料與製程產業專班 === 97 === Copper metallization has been extensively used in the silicon industry since IBM announced its success in silicon VLSI process. However, even though copper metallization has become very popular in the fabrication of Si devices, there are only a few report...
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| Format: | Others |
| Language: | en_US |
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2008
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| Online Access: | http://ndltd.ncl.edu.tw/handle/91127486388405960087 |
| Summary: | 碩士 === 國立交通大學 === 工學院半導體材料與製程產業專班 === 97 === Copper metallization has been extensively used in the silicon industry since IBM announced its success in silicon VLSI process. However, even though copper metallization has become very popular in the fabrication of Si devices, there are only a few reports on the copper metallization of GaAs devices. So developing a Cu-metallized ohmic contact for n-type GaAs to implement Cu-metallized GaAs HBTs is important. In this study, the Cu-metallized InGaP/GaAs HBTs using Pd/Ge/Cu ohmic contact to n-type GaAs and Pt/Ti/Pt ohmic contact to p+-type GaAs and Ti/Pt/Cu for interconnect metals with Pt as the diffusion barrier has been successfully fabricated.
The Pd (150 Å)/Ge (1500 Å)/Cu (1500 Å) metal structure forms a low contact resistance ohmic contact to n-type GaAs at a low annealing temperature. The lowest specific contact resistivity is 5.73 x 10-7 Ω-cm2 when annealed at 250 °C for 20 min. The common emitter I-V curves of these Cu-metallized HBTs showed similar electrical characteristics as those for HBTs metallized with conventional Au-metallized HBTs. The power efficiency of 4x20-μm2-emitter-area of Cu-metallized devices was about 37%. During both the current-accelerated stress test (100 kA/cm2 stress for 24h) and the thermal stability test (annealing at 200°C for 24 hours), the Cu-metallized HBT with Pd/Ge/Cu ohmic contact showed slightly degradation in electrical characteristics. The results show that the novel Pd/Ge/Cu ohmic contact and Pt/Ti/Pt/Cu ohmic contact can be used on Cu-metallized InGaP/GaAs HBTs, and exhibit good device performance.
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