The thermal dissociation of electrically neutral shallow-acceptor-hydrogen complexes (AH with A B, Al, Ga, and In) follows first-order kinetics over the entire annealing process, provided the isothermal anneals are performed with a reverse bias applied to the Schottky diode. The firstorder kinetics permit a precise determination of the dissociation frequency v& of the acceptorhydrogen pairs. The temperature-dependent values of vz satisfy the relation vz vo&exp( -Ez/ kT), with vos 2.8X 10' s ', voA~3. 1X10' s ', voo, 6. 9X10'3 s ', and vot"8. 4X10' s The dissociation energies E& depend only weakly on the acceptors: Es (1.28+ 0.03) eV, EA/ (1.44~0 02) eV, Eo, (1.40+'0 03) eV, and Et"(1. 42~0 05) eV. Atomic hydrogen introduced into crystalline silicon leads to a deactivation of the group-III shallow acceptors (8, Al, Ga, In, and Tl), due to the formation of an electrically neutral acceptor-hydrogen complex (AH). ' Despite intensive investigations of the structural and electrical properties of the AH complex, ' there are no reliable data on the dissociation energies E~of these pairs. The values of E~reported in the literature show a considerable scatter, ' and strongly depend on the method of hydrogenation. A precise knowledge of E~would provide an additional criterion to check the various microscopic configurations of the AH complexes proposed in the literature. ' Furthermore, an understanding of the dissociation kinetics of the AH complexes facilitates the quantitative analysis of low-temperature (T (200' C) diffusion experiments, where the hydrogen-acceptor interaction strongly modifies the H-diffusion profiles, ' and hampers a precise determination of the H diffusivity.We show that annealing of hydrogenated p-type silicon with a reuerse bias applied to a Schottky diode leads to a reactivation of the acceptor, which follows first-order kinetics throughout the entire time of annealing. The firstorder reactivation of the acceptor in the space-charge region is determined only by the dissociation frequency võ f the complex AH. From the temperature dependence of v~, we obtain the dissociation energies of the various AH pairs (A 8, Al, Ga, and In).We use 8-doped (100) float-zone silicon, Al-or Gadoped (111) Czochralski silicon, and In-doped (111) fioat-zone silicon of 10 0 cm resistivity. The samples are exposed to a radio-frequency (13 MHz) hydrogen plasma for 2 h at temperatures in the range of 120-250'C. A layer of thickness d (d 2-4 pm) below the irradiated surface is then chemically removed, and titanium Schottky contacts (1 mm diam) are evaporated. The Ohmic contact consists of an indium-gallium alloy scratched onto the back surface. Anneals at a temperature T, in the range 40-220'C with a reverse-bias Vtt applied to the Schottky diode are performed in a cryostat under ambient atmosphere. After annealing for a time T"the temperature is rapidly decreased by immersing the sample holder in liquid nitrogen with the bias on. Capacitance versus voltage [C(V)1 measurements at 1 MHz and 14 15xlQ

No abstract

No abstract

No abstract

The deactivation of the acceptor indium after chemomechanical polishing of p-type silicon is shown to result from the formation of a complex involving the indium atom and a positively charged, extremely fast-diffusing defect X. In the temperature range from 220 to 280 K, the dissociation frequency ν of this complex and the diffusion coefficient D of the defect X are thermally activated and satisfy the expressions ν=ν0 exp(−Ed/kT) and D=D0 exp(−Ea/kT) with ν0=2.6×1012 s−1, Ed=0.690 eV, D0=5×104 cm2/s, and Ea=0.665 eV.