Pallab K. Chatterjee

Photoluminescence study of native defects in annealed GaAs

Abstract Low temperature (6°K) photoluminescence measurements have been performed on GaAs annealed under various conditions, to study defects generated by outdiffusion of the constituent atoms. Several defect-related luminescence peaks have been observed and associated with Ga and As outdiffusion. The outdiffusion of these elements during annealing to 850°C in vacuum and with Ga or As overpressure and SiO 2 coatings is studied by monitoring the intensities of these peaks.

Photoluminescence from Be‐implanted GaAs

Low‐temperature (6 °K) photoluminescence data on Be‐implanted GaAs are presented. A luminescence band centered at 1.4902 eV is related to recombination involving the Be acceptor. Annealing to 900 °C with Si3N4 encapsulation is shown to optically activate the implanted Be and reorder the lattice. The ionization energy of Be is estimated to be 22±3 meV.

Temperature dependence of photoluminescence from Be‐implanted GaAs

Photoluminescence data from Be‐implanted GaAs are presented for the temperature range 3–120 °K. A luminescence band at 1.493 eV is associated with recombination from the conduction band to neutral Be acceptors, based on the temperature dependence. The binding energy of Be acceptors in GaAs is estimated to be 28.4 meV from the temperature dependence of the peak energy of this band.

Versatile double AC Hall effect system for profiling impurities in semiconductors

A versatile system is described for measuring electrically active impurity distributions in semiconductors. The system uses an improved double AC Hall system for sensitive measurement of the Hall effect in conjunction with chemical etching for removal of successive layers. All processing is done with samples mounted on standardized discs, increasing the convenience and speed of the technique for repetitive measurements. A measured profile of Be-implanted GaAs obtained with this system is presented as an example.

Luminescence in ZnSe with Na and Al doping

Abstract Photoluminescence of ZnSe doped with Na and Al has been studied. A broad band in the blue region of the spectrum has been observed at temperatures below 150 °K. This band is apparently due to donor-acceptor pair transitions involving Al donors and Na acceptors. Temperature dependence of the luminescence indicates that the Na-acceptor level is relatively shallow.

Luminescence properties of Be‐implanted GaAs1−xPx (x∼0.38)

Radiative recombination in Be‐implanted GaAs1−xPx (x∼0.38) is examined using low‐temperature photoluminescence and electroluminescence. A luminescence band at 1.955 eV (6 °K) is related to recombination from the conduction band to neutral Be acceptors. The temperature dependence of this emission band indicates the binding energy of the Be acceptor is 35±3 meV. Annealing the Be‐implanted GaAs1−xPx with SiO2 or Si3N4 encapsulation at 900 °C is shown to reorder the lattice and produce excellent optical activation. Photoluminescence measurements in conjunction with successive layer removal indicate the implanted Be does not diffuse significantly during the anneal.

Reduced lateral diffusion and reverse leakage in Be-implanted GaAs1−xPxdiodes☆

Abstract Lateral Zn diffusion under the Si3N4 mask encountered in standard red GaAs0.6P0.4 light emitting diodes can be eliminated in Be-implanted junctions. Typical reverse leakage current for implanted devices is ∼ 5nA compared with ∼ 250nA for Zn-diffused diodes.

Comment on ’’Evidence for electronic stopping in ion implantation: Shallower profile of lighter isotope 10B in Si’’

A recent paper bases several conclusions regarding electronic and nuclear stopping powers of silicon for implanted boron on a few capacitance‐voltage measurements of impurity profiles. We suggest here that the accuracy of C‐V data is insufficient to distinguish small changes in projected range, and that measurements with better resolution are required.

Electrical properties of be-implanted GaA1-xPx☆

Abstract Hall effect and resistivity measurements on Be implanted GaAs 1- x P x (x∼0.38) indicate that essentially 100% doping efficiency may be obtained for normal Be concentrations after a 900°C anneal using either SiO 2 or Si 3 N 4 as an encapsulant. The temperature dependence of hole mobility in these samples exhibits impurity banding effects similar to those reported in heavily Zn doped GaAs. Hall effect measurements in conjunction with successive thin layer removal techniques indicate there is no significant diffusion of the implanted Be during anneal for a fluence of 6×10 13 ions/cm 2 .

Impurity Distribution of Ion-Implanted Be in GaAs by Sims, Photoluminescence, and Electrical Profiling

Atomic, optically active, and electrically active profiles measured for 250 keV ion-implanted Be in GaAs as a function of fluence have been correlated. Be atomic depth profiles were obtained by secondary-ion mass-spectroscopy (SIMS) techniques. Photoluminescence and Hall effect measurements made in conjunction with successive layer removal were used to obtain the optically and electrically active profiles. Atomic SIMS profiles obtained from samples implanted to a fluence of 6X10113cm-2 showed no major distribution changes after a 900°C, 30 min anneal treatment. Electrically active profiles obtained from duplicate samples had distributions which were similar to the SIMS results. Hall effect and resistivity measurements after annealing indicated nearly complete electrical activity of the implanted Be, with mobility values typical of p-type bulk material.