Micromorphology and defects of non-doped gallium arsenide layers

Electron microscopy was used to study non-doped GaAs layers obtained in a chloride system Ga-AsCl₃-H₂. Electron concentrations is 10¹³–10¹⁵ cm⁻³, mobility at liquid nitrogen temprature reaches 200000 cm²/v. sec. It is shown that a fraction of the growth surface taken with (110) faces is less for films with less electron concentration. The main type of defects in pure GaAs layers is precipitates at pinning centres of growth steps. Estimations based on microdiffraction patterns and irradiation effects show that the impurity concentration in them is 10¹⁶–10¹⁹ cm⁻³. The impurity in precipitates is assumed to be electrically non-active, mainly, in interstitial positions.