| About this Abstract |
| Meeting |
2011 Electronic Materials Conference
|
| Symposium
|
2011 Electronic Materials Conference
|
| Presentation Title |
T7, Highly Reproducible Growth of Carbon Nanotubes for Practical Applications in Electronics |
| Author(s) |
Yohei Yagishita, Daiyu Kondo, Ikuo Soga, Taisuke Iwai |
| On-Site Speaker (Planned) |
Yohei Yagishita |
| Abstract Scope |
Carbon nanotubes (CNTs) are promising candidates for LSI interconnects and heat-dissipation bumps in the future [1, 2] because of their tolerance to higher current density and their higher thermal conductivity than that of copper used generally in electronics. Highly reproducible and uniform growth of CNTs with a high CNT density (>10<SUP>10</SUP>/cm<SUP>2</SUP>) and definite length (10–100 μm) has to be realized so that the practical use of CNTs in such applications can be achieved. However, it has been observed that the reproducibility in terms of CNT length and density is low in the case of growth of CNTs at a low density (~10<SUP>9</SUP>/cm<SUP>2</SUP>) on a silicon substrate. In this study, we have demonstrated a highly reproducible and uniform growth of CNTs with high CNT density. CNTs were grown by thermal chemical vapor deposition (CVD). The CVD process was carried out in a vacuum chamber with a load-lock system. A mixture of acetylene and argon gases was used as the carbon source and introduced into the CVD chamber. The substrate temperature and total pressure were around 650°C and 1–4 kPa, respectively. To maintain the same CNT growth conditions, the temperature deviation from the growth temperature (±5.7°C) was improved to be below ±1.0°C. An iron film sputtered on a silicon substrate with 300-nm-thick silicon dioxide was used as the catalyst. The iron films had a thickness of 1.0 to 5.0 nm. By optimization of the CVD process, we achieved high reproducibility in terms of CNT length (deviation of CNT length: 11%), which was less than half the reproducibility achieved previously (deviation of CNTs length: 28%). In addition, uniform growth of CNTs across the 3-inch substrate (deviation of CNTs length: 1.5%) was achieved under the same optimized conditions; this uniform growth might be because the temperature deviation in the CVD chamber is small. These results imply that low temperature deviation from the growth temperature is important for achieving good reproducibility and uniformity. Moreover, synthesis of CNTs with a higher density (~10<SUP>10</SUP>/cm<SUP>2</SUP>) was performed by optimizing the CVD conditions. Finally, the electrical properties of CNT bundles synthesized by optimizing the growth conditions were measured and compared with the electrical properties of CNTs obtained before optimization. The electrical properties of CNT bundles synthesized by optimizing the growth conditions were considerably better than those reported previously [2]. This clearly indicates that the density of CNTs synthesized by adopting the present optimized CVD conditions is higher than that of CNTs synthesized before optimization. |
| Proceedings Inclusion? |
Undecided |