Thermal stability of the electrical isolation in n-type gallium arsenide layers irradiated with H, He, and B ions

The stability of the electrical isolation in n-type GaAs layers irradiated with ions of different mass is compared. The irradiations were performed with proper doses of H-1(+), He-4(+) or B-11(+) ions to create specific damage concentration level which lead to: (i) the trapping of practically all the carriers (R(s) approximate to 10(8) Ohm/square), (ii) the onset of hopping conduction (R(s) approximate to 10(8) Ohm/square), and (iii) a significant hopping conduction (R(s) approximate to 10(6) Ohm/square). Irrespectively of the ion mass, the temperature range for which the isolation is preserved, i.e., R(s)>10(8) Ohm/square, extends up to 200 or approximate to 600 degrees C, respectively, for the cases (i) and (ii). In case (iii), this range comprises temperatures from approximate to 400 to 650 degrees C. Annealing stages at 200 and 400 degrees C recover in a great extent the conductivity and improve the carrier mobility in low dose irradiated samples [case (i)]. In samples irradiated to higher doses [cases (ii) and (iii)], the conductivity recovers in a single stage. (C) 1996 American Institute of Physics.