A. E. Kalyadin

Si:Si LEDs with room-temperature dislocation-related luminescence

Silicon-based light-emitting diodes (LEDs) fabricated by the Si-ion implantation and chemical-vapor deposition methods are studied. Room-temperature dislocation-related electroluminescence (EL) is observed in LEDs based on n-Si. In LEDs based on p-Si, the EL is quenched at temperatures higher than 220 K. The EL-excitation efficiencies are measured for the D1 line at room temperature and the D1 and D4 lines at liquid-nitrogen temperature.

Dislocation-related photoluminescence in silicon implanted with fluorine ions

The implantation of 85-keV fluorine ions at a dose of 8.3 × 1014 cm–2 into single crystal Si does not lead to formation of an amorphous layer. Subsequent annealing at a temperature of 1100°C in a chlorine-containing atmosphere is accompanied by the appearance of D1 and D2 lines of dislocation-related luminescence. The intensity of both lines decreases as the annealing duration is increased from 0.25 to 3 h. As the measurement temperature is increased from 80 to 200 K, the intensities of these lines decrease and the positions of their peaks shift to longer wavelengths.

Effect of the implantation dose and annealing time on the luminescence properties of (113) defects in silicon implanted by oxygen ions

The photoluminescence properties of (113) defects formed in a silicon structure after the implantation by oxygen ions with an energy of 350 keV and doses of 1.7 × 1013–1.7 × 1015 cm–2 and the subsequent annealing at a temperature of 700°C for 0.5–2.0 h in a chlorine-containing atmosphere have been investigated. Regardless of the implantation dose and annealing time, the photoluminescence spectra are dominated by the line at a wavelength of 1.37 μm, which is attributed to a (113) defect. The dependences of the line intensity on the implantation dose and annealing time are characterized by curves with maxima. As the measurement temperature increases in the range from 64 to 120 K, the line intensity decreases monotonically.

Luminescent and Structural Properties of Self-Implanted Silicon Layers in Relation to their Fabrication Conditions

Luminescent and structural properties of silicon layers with dislocation-related luminescence have been studied. Silicon ions (100 keV) were implanted into n-FZ-Si wafers at a dose exceeding the amorphization threshold by two orders of magnitude. The implantation was not followed by amorphization of the implanted layers. A post-implantation annealing resulted in the formation of luminescence centers and extended structural defects. Some fundamental aspects and specific features in the properties of dislocation-related luminescence lines and extended structural defects were revealed in relation to the annealing conditions.

Photoluminescence in silicon implanted with silicon ions at amorphizing doses

Luminescent and structural properties of n-FZ-Si and n-Cz-Si implanted with Si ions at amorphizing doses and annealed at 1100°C in a chlorine-containing atmosphere have been studied. An analysis of proton Rutherford backscattering spectra of implanted samples demonstrated that an amorphous layer is formed, and its position and thickness depend on the implantation dose. An X-ray diffraction analysis revealed that defects of the interstitial type are formed in the samples upon annealing. Photoluminescence spectra measured at 78 K and low excitation levels are dominated by the dislocation-related line D1, which is also observed at 300 K. The peak position of this line, its full width at half-maximum, and intensity depend on the conduction type of Si and implantation dose. As the luminescence excitation power is raised, a continuous band appears in the spectrum. A model is suggested that explains the fundamental aspects of the behavior of the photoluminescence spectra in relation to the experimental conditions.

The Effect of Dose of Nitrogen-Ion Implantation on the Concentration of Point Defects Introduced into GaAs Layers

Secondary-ion mass spectrometry and Rutherford proton backscattering have been used to measure the concentration profiles of nitrogen atoms and examine the defect structure of epitaxial GaAs layers implanted with 250-keV N+ ions at doses of 5 × 1014–5 × 1016 cm–2. It was found that no amorphization of the layers being implanted occurs at doses exceeding the calculated amorphization threshold, a concentration of point defects that is formed is substantially lower than the calculated value, and a characteristic specific feature of the defect concentration profiles is the high defect concentration in the surface layer.

Photoluminescence in silicon implanted with erbium ions at an elevated temperature

Photoluminescence spectra of n-type silicon upon implantation with erbium ions at 600°C and oxygen ions at room temperature and subsequent annealings at 1100°C in a chlorine-containing atmosphere have been studied. Depending on the annealing duration, photoluminescence spectra at 80 K are dominated by lines of the Er3+ ion or dislocation-related luminescence. The short-wavelength shift of the dislocation-related luminescence line observed at this temperature is due to implantation of erbium ions at an elevated temperature. At room temperature, lines of erbium and dislocation-related luminescence are observed in the spectra, but lines of near-band-edge luminescence predominate.

Electroluminescence properties of LEDs based on electron-irradiated p -Si

The electroluminescence (EL) in n+–p–p+ light-emitting-diode (LED) structures based on Si irradiated with electrons and annealed at high temperature is studied. The LEDs are fabricated by the chemical- vapor deposition of polycrystalline silicon layers doped with high concentrations of boron and phosphorus. Transformation of the EL spectra with current in the LEDs is well described by six Gaussian curves. The peak positions of these curves are current-independent and equal to 1233, 1308, 1363, 1425, 1479, and 1520 nm. The dependences of the integrated EL intensity and of the full-width at half-maximum (FWHM) of the lines on current are examined.

Effect of the fabrication conditions of SiGe LEDs on their luminescence and electrical properties

SiGe-based n+–p–p+ light-emitting diodes (LEDs) with heavily doped layers fabricated by the diffusion (of boron and phosphorus) and CVD (chemical-vapor deposition of polycrystalline silicon layers doped with boron and phosphorus) techniques are studied. The electroluminescence spectra of both kinds of LEDs are identical, but the emission intensity of CVD diodes is ∼20 times lower. The reverse and forward currents in the CVD diodes are substantially higher than those in diffusion-grown diodes. The poorer luminescence and electrical properties of the CVD diodes are due to the formation of defects at the interface between the emitter and base layers.

Temperature dependences of the photoluminescence intensities of centers in silicon implanted with erbium and oxygen ions

Low-temperature photoluminescence in n-Cz-Si after the implantation of erbium ions at an elevated temperature and subsequent implantation of oxygen ions at room temperature is studied. So-called X and W centers formed from self-interstitial silicon atoms, H and P centers containing oxygen atoms, and Er centers containing Er3+ ions are observed in the photoluminescence spectra. The energies of enhancing and quenching of photoluminescence for these centers are determined. These energies are determined for the first time for X and H centers. In the case of P and Er centers, the values of the energies practically coincide with previously published data. For W centers, the energies of the enhancing and quenching of photoluminescence depend on the conditions of the formation of these centers.