Profiles of ion-doped layers on gallium arsenide

Abstract

We studied the concentration profiles of charge carriers that are characteristic for ion-doped layers (IDL) used in the manufacturing of field-effect transistors with a Schottky barrier (FTS) on gallium arsenide. Silicon was used as a dopant in the formation of n- and n⁺ -n layers on GaAs. During annealing of the IDL, SiO₂ films were used as protective coatings. The impurity content and silicon distribution in the IDL were estimated by the SIMS method. Profiles of ion-doped layers were calculated by the LSB method. The method for measuring of surface concentration consists in the constant chemical etching of thin layers of gallium arsenide and the measurement of surface electrophysical characteristics. The experimental concentration profiles for GaAs are not Gaussian, but have wide “tails” due to channeling effects in crystals and the influence of chromium. The modes of ion implantation are considered, which form IDL with a sharper profile of the concentration of charge carriers in the “tail”.