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Nanostructure ITO thin films have been deposited on well cleaned glass and silicon substrates using dc magnetron sputtering technique. The ITO films are post annealed in air using a normal heater setup in the temperature range 100 - 400 ˚C. The ITO film annealed at 300˚C exhibited optimum transparency and resistivity values for device applications. The thickness of the ITO thin films is determined using DEKTAK stylus profilometer. The sheet resistance and resistivity of the ITO films were determined using four probe technique. Finally, the optimized nanostructure ITO layers are incorporated on silicon solar cells and the efficiency of the solar cell are found to be in the range 12-14%. Other solar cell parameters such as fill factor(FF), open circuit voltage(Voc),Short circuit current(Isc), series resistance(Rs) and shunt resistance(Rsh) have been determined. The effect of ITO film thickness on silicon solar cells is also observed.

Indium tin oxide (ITO) thin films exhibiting good transmittance and conductivity suitable for solar cell applications have been prepared on Si(100) and fused silica substrates by optimizing the dc sputtering parameters such as power density and Ar partial pressure. Structural analysis of the as-deposited and annealed ITO films indicated that the as-deposited films are predominantly amorphous, whereas the films annealed at 200–400 ˚C are found to be of polycrystalline nature exhibiting dominant peaks corresponding to the (222) and (400) planes. The optical transmittance and band gap values of the films are observed to exhibit a change on annealing. From the ellipsometry studies on ITO/Si annealed at 300˚C, it is found that graded layer consist of the mixing of two ITO materials with slightly different optical constants and the grading is almost linear. The resistivity of the ITO films is found to decrease with annealing temperature, correlating with the improvement in the crystal quality, and values in the range of 2-3 x10-4 Ω-cm are observed for the films annealed at 300˚C. Surface topography study of the films has been performed using atomic force microscope(AFM) and the results are discussed.

A review of our recent experimental investigations of dopant diffusion and characterization of electrically active defect complexes in strained and relaxed epitaxial SiGe/Si heterostructures is given. Three topics: (i) Sb and P diffusion, (ii) properties of divacancy and P-vacancy complexes, and (iii) thermal donor generation in SiGe are discussed in detail. High resolution X-ray diffraction (HRXRD), secondary ion mass spectrometry (SIMS), deep-level transient spectroscopy (DLTS), admittance spectroscopy (ADSPEC) and thermally stimulated capacitance (TSCAP) have been employed for the relaxation control, tracer profiling, deep- and shallow-level characterization in our samples. A part of the electrical measurements is performed in MOS Si/SiGe/Si components.

Platinum has been diffused into epitaxial n-type silicon at 600, 650, and 700°C for 30 min following implantation with 3.3 MeV alpha particles. The doses employed were between 1×1011and 1×1014He+cm−2. Thereafter the samples were characterised using DLTS (deep level transient spectroscopy). The samples diffused at 700°C show only the deep level at 0.23 eV below the conduction band that is attributed to substitutional platinum. DLTS profiling reveals a decoration of the region of maximal damage by the platinum for lower doses while for higher ones the platinum concentration is observed to decrease or vanish in this region. In addition, other deep levels may appear (so-called K-lines). As the implantation dose increases, so does the platinum concentration following diffusion at 700°C at the shallow end of the DLTS working region. It is shown that by controlling the amount of implantation induced defects and the diffusion temperature one can steer the amount of platinum that arrives in the region of maximal damage. The stability of the defect decoration has also been studied by varying the diffusion times at 700°C from 10 to 50 min. For diffusion times longer than 30 min a reduction in the maximum platinum concentration is observed. It is assumed that the platinum diffuses further into the bulk.

Infrared absorption from oxygen-related defects in Si crystals irradiated with electrons (2.5MeV) at room temperature (RT) and in the range 300–600°C has been investigated. Two new vibrational bands positioned at 10K at about 1370 and 1430cm−1were observed in samples irradiated at RT. A good correlation is found between these lines and the bands at 836 and 885cm−1known to originate from asymmetrical stretching vibrations (B1mode) of an oxygen atom in the neutral and negative VO complex. An attribution of the 1370 and 1430cm−1bands to a combination of the B1mode with the symmetrical stretching A1mode (weakly IR active) for different charge states of VO is argued to be the most probable. A band at 833.4cm−1is found to increase in strength upon annihilation of divacancies at 250–300°C. The V2O complex is suggested to give rise to this band. New experimental data confirming an attribution of the 895cm−1band to the VO2complex are presented as well.

4H–SiC n-type epi-material of nitrogen doped of 1×1015cm−3was implanted with low doses of B and He ions. The doses chosen were extremely low, 1×107–8×107cm−2, to avoid dopant compensation. Deep level transient spectroscopy and capacitance–voltage measurements was then performed on the samples without needing an intermediate anneal to restore doping activation. Two levels were found in the energy band gap, Ec−0.70±0.02 and Ec−1.6±0.07eV. The Ec−0.70 level was found to grown linearly with dose and implantation temperature of 500°C reduced the Ec−0.70 level concentration.

Electrically active shallow centers in silicon obtained by low-temperature silicide mediated crystallization were investigated. In addition to the phosphorous related level (L1) a second shallow level (L2  30 meV below the conduction band) was observed and attributed to oxygen related donors. L2 appears with a high concentration and dominates the electrical characteristics of the recrystallized silicon layers. Schottky barrier junctions formed on these layers display a pronounced tunneling behavior, attributed to the high concentration of L2 centers in the near surface region.

Czochralski-grown phosphorus-doped (2 × 1014 cm—3) silicon wafers have been annealed in nitrogen, wet nitrogen, argon, oxygen, and vacuum ambients at 470 °C for times up to 500 h. Sample characterization was made with capacitance–voltage, four-point probe, DLTS, thermally stimulated capacitance, admittance spectroscopy, secondary ion-mass spectrometry, and Fourier transform infrared spectroscopy. This study finds a strong relation between the previously reported ultra-shallow thermal donors (USTDs) and shallow thermal donors (STDs), and it is shown that the net concentration of thermally formed donors is independent on annealing ambient within the experimental accuracy. It was found that the majority of formed donors for long anneals consisted of either STDs or USTDs, however, it was found that oxygen-containing ambient is indispensable for forming USTDs.

The diffusion and passivating effect of hydrogen (isotope 2H) in epitaxial p-type SiC is studied by secondary ion mass spectrometry and capacitance–voltage profiling on Schottky diodes. The incorporation of hydrogen is achieved by low-energy ion implantation. The influence of implantation energy, temperature and subsequent annealing is presented. Annealing experiments with an electric field applied reveal a reactivation of passivated acceptors and a H+ ion drift at a surprisingly low temperature of 530 K.

Broadening of secondary ion mass spectrometry depth profiles for Al in Al0.5Ga0.5As/GaAs structures, where the layer thicknesses vary from two monolayers to 1000 Å, is investigated. The experiments were performed in the net primary energy range 1.8–13.2 keV with 40Ar+ions and 84Kr+ions. The broadening is mainly determined by ballistic mixing, and no dependence on the Al0.5Ga0.5As layer thickness is revealed. Good agreement is found with a semi-empirical mixing model published recently by Zalm and Vriezema and [Nucl. Instr. and Meth. B 67 (1992) 467] although a small contribution from surface roughness occurs. The surface roughness develops initially but saturates already after the first Al0.5Ga0.5As layer.

This paper reviews recent secondary ion mass spectrometry (SIMS) work on (i) isotope shifts in ion implantation profiles, (ii) dopant profiles in silicon and beam-induced oxidation and (iii) surface roughness and profile broadening of AlxGa1-xAs/GaAs superlattice structures. Comparison is made with other techniques, and, in particular, the issues of depth resolution and conversion between sputtering time and sample depth are emphasized.