AVS 45th International Symposium
    Surface Science Division Monday Sessions
       Session SS-MoP

Paper SS-MoP27
A New GaCl Molecular Beam Cell for Surface Dynamic Studies

Monday, November 2, 1998, 5:30 pm, Room Hall A

Session: Surface Science Division Poster Session
Presenter: M. Ohashi, JRCAT-ATP, Japan
Authors: M. Ohashi, JRCAT-ATP, Japan
M. Ozeki, JRCAT-ATP, Japan
Correspondent: Click to Email
An understanding of the surface reaction dynamics between source molecules and solid surface is required for the development of an advanced technological base for III-V semiconductor growth. Gallium chloride (GaCl) is one of the most important sources for III-V epitaxial growth. GaCl has an advantage of controlled chemical reaction, because it easily dissociates with H@sub 2@ on GaAs surface in spite of its strong bonding. However it is necessary to produce GaCl in-situ in the production cell, because GaCl preferably exists at higher temperature above 870 K. In order to study the surface reaction dynamics between GaCl molecule and GaAs surface, high purity GaCl molecular beam is necessary. We developed a new GaCl molecular beam cell, where high purity GaCl molecular beam was produced by direct reaction between Ga metal and Cl@sub 2@ gas. We optimized the gas flow rate of Cl@sub2@ gas for the production of GaCl molecular beam and the cell temperature from 920 to 1230 K. The byproduct of GaCl@sub 3@, which is stable and form large particles at low temperature, was observed under excess supply of Cl@sub 2@ gas. Under the optimized condition, which is the gas flow rate of Cl@sub 2@ at .25 ccm, the only GaCl was produced and no Cl@sub 2@ was observed. The Flux density at the sample surface, which is 40 cm away from the nozzle of this cell, was estimated 1.1x10@super 13@ molecules cm@super -2@ s@super -1@. The newly developed GaCl molecular beam cell would be useful for the study of the surface reaction dynamics between GaCl source and GaAs surface. This work is supported by New Energy and Industrial Technology Development Organization (NEDO).