Ga Samples Research Articles

Hall effect measurements on Sb and Ga implanted silicon; Anneal behavior and comparison with other species

AbstractAnalyses ofn- andp-type silicon samples implanted with 50 keV Ga and 40 keV Sb ions at substrate temperatures of 350°C and room temperature were made by use of Hall effect and sheet resistivity measurements. It was found that the presence of an amorphous layer formed during implantation has a major effect on the anneal characteristics. For Sb and Ga samples implanted at room temperature to doses ≳ 1014/cm2, a large increase in the number of carriers per cm2,Ns, was observed after anneal at temperatures of ≈ 550°C. The maximum value ofNs was found for anneal temperatures of 550-600°C. This temperature corresponds to the reordering of an amorphous layer as observed in channeling effect measurements. At an anneal temperature of 900°C, the concentration of carriers/cm3 exceeded the thermal equilibrium solubility value for Sb implantations and was comparable to this value for Ga. In both high dose (≈ 2·1014/cm2) 350°C and low dose (≈ 1013/cm2) room temperature implantations of both species, the anneal behavior was similar; here anneal temperatures of ≈ 800°C were required to obtain the maximum value ofNs and no anneal stage was observed at 550°C.

Electron Scattering at a Rough Surface

The lifetime of electrons in a skipping trajectory is limited by an occasional diffuse-surface-scattering event that removes the electron from a given quantum energy level. For elastic transitions between surface states, the scattering rate ${\ensuremath{\Gamma}}_{s}$ is predicted to become larger with increasing magnetic field as ${H}^{2}$. Such increasingly nonspecular surface reflection has been observed in a series of Ga and Sn samples with deliberate and controlled surface roughness.

Conduction Band Minima ofGa(As1−xPx)

Photoresponse of surface barriers on samples of Ga(As_(1−x_P_x) covering the range 0≤x≤1 has been measured. Thresholds corresponding to both direct and indirect band-to-band excitations within the semiconductor and also photoinjection from the metal have been identified. The threshold of the direct transition varies with composition from 1.37 eV in GaAs to 2.65 eV in GaP. The indirect transition was followed for x≳0.38 and again varied linearly from 2.2 eV in GaP to an extrapolated value in 1.62 eV in GaAs. The energy separation of the two conduction band minima in GaAs is in disagreement with previously reported values.