Vapor Growth Parameters and Impurity Profiles on N-Type GaAs Films Grown on N[sup +]-GaAs by the Hydrogen-Water Vapor Process

Controlled growth of very smooth n‐type films of on substrates has been achieved with the hydrogen‐water vapor transport process. These films are grown at 1000° and 1050°C at growth rates from 0.080 to 1.5 µ min −1 with partial pressures of water vapor of atm and total flow rates from 300 to 600 cc min − 1 . The impurity profiles of these films have been determined from differential capacitance‐voltage measurements on gold surface barrier diodes. These profiles show that films grown on Si‐doped substrates have much steeper impurity gradients at the substrate‐film interface than those grown on Te‐doped substrates. Films grown on Te‐doped substrates at low flow rates become graded with a slope of about one decade per micron. These results suggest that outdiffusion from the substrate controls the profiles of thin films. The minimum net donor concentration in the films is . Reverse bias breakdown voltages of the gold diodes range from 〉 200 to 5–7v for 11µ and 1µ thick films, respectively.