Reduction of gallium‐related oval defects

A novel gallium effusion cell consisting of a sapphire crucible in a variable temperature profile furnace was used to grow GaAs layers. The effect of the gallium source temperature profile on gallium source‐related oval defects was investigated. By minimizing gallium droplets in the orifice, the gallium‐related oval defect density was reduced to <50 cm⁻² for a 1‐μm‐thick layer. These results indicate that oval defect densities can be further reduced by eliminating gallium droplets in the crucible orifice.