Production of epitaxial layers by vapor deposition utilizing dynamically adjusted flow rates and gas phase concentrations

摘要

Epitaxial layers of single crystals of gallium arsenide and similar compounds are formed by vapor deposition. A carrier gas flow is passed through a liquid halide of a group VB material to obtain a first vapor having a halogen, carrier gas and group VB material. The carrier gas flow is monitored and adjusted to obtain a predetermined mass of halogen and second material in this raw vapor. A final reactor input vapor is obtained with constant concentration and constant flow going into a reactor by monitoring the total volume of carrier gas in the raw vapor as added per unit of time and adjusting the raw vapor by adding a volume of additional carrier gas to a predetermined value to form a final reactor input vapor. The reaction and deposition of the epitaxial layer is then carried out in a reactor. A system is used for obtaining constant flow within the reactor with addition of dopants at desired levels while maintaining a constant dilution to the input flow so as to maintain at a deposition substrate, a predetermined constant flow or concentration of amount of reactants to carrier and diluent gas used.