Epitaxial Growth of Al on Si By Gas-Temperature-Controlled CVD
- PDF / 1,269,709 Bytes
- 6 Pages / 420.48 x 639 pts Page_size
- 122 Downloads / 200 Views
EPITAXIAL GROWTH OF Al ON Si BY GAS-TEMPERATURE-CONTROLLED
Tsukasa KOBAYASHI, Atsushi SEKIGUCHI, Naokichi HOSOKAWA, Tatsuo ASAMAKI ANELVA Corporation, Yotsuya 5-8-i, Fuchu, Tokyo 183
CVD
and
ABSTRACT Epitaxial AI(111) film was deposited on Si(lll) by low-pressure chemical vapor deposition with the use of tri-isobutyl aluminum (TIBA) at the substrate temperature of 400 *C with the deposition rate of 0.9 Am/min. It was necessary for epitaxy to preheat the TIBA gas just before the deposition on the substrate. The preheat was made by gas-temperature-controller provided in the chamber. The film surface was so smooth that reflectance was higher than 90 %. The film was recognized as a single crystal over the entire surface of 4-in. wafer. The film contained about 0.1 % of Si and 20 ppm of 0, C, and H. No hillock appeared on the film after 430 'C annealing for 40 min. The interface of Al and Si was rather stable so that no alloy penetration occured. The possibility of epitaxial growth of AI(100) on Si(100) was also shown. INTRODUCTION Aluminum and aluminum alloy films are widely used for metallization in VLSI processing. These films are currently deposited by the magnetron sputtering technique. However, this results in insufficient step coverage for a narrow and deep hole of submicron size with increasing integration density of IC's. The low pressure chemical vapor deposition (LPCVD) of aluminum films have been recognized as a potential technology. 1-7) However, it has been very difficult to obtain a smooth surfaced film. On the other hand, Holtzl tried to obtain fine-grained silicon carbide film by controlled nucleation thermochemical deposition (CNTD). ) They preheated the reactant gases to make appropriately activated or decomposed unstable molecules, which arrived onto the heated substrate to form a smooth surfaced film by the complete decomposition. Matsumoto et al. tried another preheating activation process in CVD with tungsten filament to 9 obtain a diamond film from CH 4. ) In Aluminum CVD, Solanki et al. made an unstable intermediate product by laser from trimethyl aluminum to obtain a smooth surfaced film.10) Thus, preheating of reactant gases has been sometimes effective to improve the flattness of films in CVD. In this work, the epitaxial growth of aluminum film is attempted with the use of TIBA by a newly developed LPCVD technique referred to as "gas-temperature-controlled CVD" (GTC-CVD). A gas-temperature-controller was equiped in the process chamber to preheat the reactant."1) Though it has been known that aluminum films were grown epitaxially on alkalihalide and silicon by physical vapor deposition (PVD) such as evaporation and ionized cluster beam deposition," 16) epitaxial growth of Al on Si by CVD was found to be possible time. 17) for the first
Mat. Res. Soc. Symp. Proc. Vol. 131. c1989 Materials Research Society
364
EXPERIMENTS Two different reactors were used. These constructions and the film formation processes were almost same except the reactor size and a load lock chamber. The reactors we
Data Loading...
