We report the application of Deep Level Transient Spectroscopy (DLTS) in Hg1-xCdxTe, demonstrating for the first time the utilization of DLTS techniques in a narrow band-gap semiconductor, Eg < 0.40 eV. DLTS measurements performed on an n+-p diode with Eg (x=0.21, T=30 K) =0.096 eV have identified an electron trap with an energy of Ev + 0.043 eV and a hole trap at Ev + 0.035 eV. Measurements of trap densities, capture cross sections, and the close proximity of the electron and hole trap locations within the band-gap suggest that DLTS may be observing both the electron and hole capture at a single Shockley-Read recombination center. The trapping parameters measured by DLTS predict minority carrier lifetime versus temperature data to be comparable with the experimentally measured values. 相似文献
We discuss DLTS andC-V measurements on Al/Si3N4/Si(2nm)/n-GaAs (≈ 5×1017 cm?3) structures. Three discrete deep traps superimposed on a U-shaped interface-state continuum have been identified, with respective thermal energies:Ec?0.53 eV,Ec?0.64 eV, andEv+0.69 eV. The second one (0.64 eV) is presented as an electric field sensitive level, its enhanced phonon-assisted emission resulting in a rapid shift of the corresponding DLTS peak to lower temperatures, as the applied (negative) reverse bias voltage increases. An interpretation through emission from the quantum well, introduced by means of the intermediate ultrathin Si layer, has failed. 相似文献
Deep-level profiles were measured radially acrossn-type FZ silicon wafers containing A-swirl defects by applying DLTS to an array of Schottky contacts. The trapparameters were
obtained very accurately using a computer-fit procedure for the full DLTS peaks. Two acceptor levels atEc−0.49 eV (σn=6.6×10−16cm2) andEc−0.07 eV (σn =4.6×10−16cm2) were observed, which varied oppositely to the A-swirl defect density. At short ranges (1–2mm) the trap concentration-profile
was smeared out and did not follow the strong fluctuations in the etch pattern. Both levels were measured together with the
same concentration. The profiles indicate outdiffusion. A level atEc−0.14 eV (σn=1.1×10−16cm2) was not related to A-swirl defects. A level atEc−0.11 eV (σn=1.1×10−15cm2) was only detected in one ingot.
The properties of the deep level atEc−0.49 eV are discussed in the light of published DLTS results reported for γ-irradiation, laser annealing after self-implantation,
annealing under pressure and oxidation of silicon samples. It is concluded, that this level is related to interstitial silicon
rather than to an impurity. 相似文献
Deep levels in iron-dopedp-type silicon are investigated by means of Deep Level Transient Spectroscopy (DLTS) and the Hall effect. Pairs of Fe with the acceptors B, Al, and Ga are observed at 0.1, 0.19, and 0.24 eV above the valence band edgeEv. For interstitial iron, (Fei), a level energy ofEv+0.39+-0.02 eV is obtained with DLTS after correction with a measured temperature dependence of the capture cross section. The Hall effect yieldsEv+0.37 eV for Fei. The annealing behavior of levels related to Fe is investigated up to 160 °C. Iron participates in at least four different types of impurity states: Fei, Fe-acceptor pairs, precipitations (formed above 120 °C) and an additional electrically inactive state, which is formed at room temperature. 相似文献
Two new DLTS bands I and II have been observed in n-type germanium containing 1016 cm-3 interstitial oxygen. The signature of II is: Ec?EII = 0.031 eV, K = 4 × 107 cm?2s?1; level I is about half as deep. In addision, the excitation spectrum of I is recorded by PTIS. It is composed of three hydrogenic donor series Ia, b, c with activation energies 17.25, 17.6 and 18.1 meV. The donors I and II are thought to correspond with the well known thermal oxygen donors. Energies for the latter were determined at 0.017 and 0.04 eV from Hall effect by Fuller and Doleiden. The possibility of double donors is examined, in analogy with the case of oxygen donors in silicon. 相似文献
New samples of the Bi2Zn0.1–xTixV0.9O5.35+x; 0.02 ≤ x ≤ 0.08 system have been synthesized through a standard solid-state reaction route. XRD analysis and differential thermal analysis have been used to characterize the phase structure of samples. The γ′ phase is stabilized to room temperature in all investigated samples. The electrical properties of the BIZNTIVOX system have been studied by using AC impedance spectroscopy. An AC impedance response as a function of frequency (20 Hz–1 MHz) has been used to investigate the electrical conductivity and the dielectric permittivity in the temperature range of 150 °C–700 °C. In this temperature range, the phase transition γ′ to γ has been observed in all the compositions studied. AC impedance spectroscopy indicates that the resistance of samples decreases with increase of temperature. The ionic conductivity of samples appeared as a two-line region in Arrhenius dependence. At 300 °C, the highest ionic conductivity is shown by the composition x = 0.05 (σ300 = 1.35 × 10?4 S cm?1). 相似文献
HfLaOx based Metal–oxide–semiconductor capacitors were fabricated by atomic layer deposition in this work. The material and electrical properties of the films along with the high temperature thermal treatment were investigated. It was found that samples undergoing annealing at 900 °C exhibited the best performance. The film was found to be crystallized to a cubic structure at 900 °C, and the roughness of the films was estimated to be 0.332 nm. For electrical characterization, the C–V curve of the film is in good agreement with the corresponding simulated curve, and the capacitor does not show any hysteresis. Moreover, the Dit near the center of silicon band gap exhibits lowest value, and it was calculated to be 2.28 × 1011 eV?1 cm?2. 相似文献
Defects created in rapid thermally annealed n-GaAs epilayers capped with native oxide layers have been investigated using
deep-level transient spectroscopy (DLTS). The native oxide layers were formed at room temperature using pulsed anodic oxidation.
A hole trap H0, due to either interface states or injection of interstitials, is observed around the detection limit of DLTS
in oxidized samples. Rapid thermal annealing introduces three additional minority-carrier traps H1 (EV+0.44 eV), H2 (EV+0.73 eV), and H3 (EV+0.76 eV). These hole traps are introduced in conjunction with electron traps S1 (EC-0.23 eV) and S2 (EC-0.45 eV), which are observed in the same epilayers following disordering using SiO2 capping layers. We also provide evidence that a hole trap whose DLTS peak overlaps with that of EL2 is present in the disordered
n-GaAs layers. The mechanisms through which these hole traps are created are discussed. Capacitance–voltage measurements reveal
that impurity-free disordering using native oxides of GaAs produced higher free-carrier compensation compared to SiO2 capping layers.
Received: 12 March 2002 / Accepted: 15 July 2002 / Published online: 22 November 2002
RID="*"
ID="*"Corresponding author. Fax: +61-2/6125-0381, E-mail: pnk109@rsphysse.anu.edu.au 相似文献
Tellurium-related defects inn-type silicon have been analysed by deep level transient spectroscopy (DLTS). The tellurium doping of the samples was performed by ion implantation or during epitaxy. In all the samples, a level having a thermal activation energy around 0.37 eV is observed. This activation energy is found to be dependent on the electric field. Taking into account the Poole-Frenkel (FP) effect and a temperature dependence proportional toT?2 in the capture cross-section, a value ofEA=0.41eV is obtained. A second Te-related level having an activation energy ofEA=0.14eV without correction of the FP effect could only be measured in the implanted samples. The same concentration is observed for the two levels in the implanted samples thus indicating that both peaks in the DLTS spectra are caused by the identical Te-related defect. 相似文献
Quantum dots (3–4?nm) of Zn1?xCdxS (both free of Mn2+ and with Mn2+ incorporated) were synthesized through a novel solvothermal-microwave irradiation technique. Detailed structural analysis of the Zn1?xCdxS and Zn1?xCdxS:Mn2+ (x?=?0, 0.25, 0.5, 0.75 and 1) materials was carried out using powder X-ray diffraction technique. For all the compositions, the crystallite size was controlled to less than 1.5?nm. The optical energy gap for Zn1?xCdxS was found to vary from 3.878 to 2.519?eV and for Zn1?xCdxS:Mn2+ it varies from 3.830 to 2.442?eV when x is increased from 0 to 1. Overall, the optical energy gap could be tuned from a minimum of 2.442?eV to a maximum of 3.878?eV. DC conductivity analysis (from 40°C to 150°C) and electrical energy gap analysis for all the compositions were also performed. The dc conductivity for Zn1?xCdxS solid solutions varies from 0.3840?×?10?10 to 8.7782?×?10?10?mho/m at 150°C and for Zn1?xCdxS:Mn2+ it varies from 0.5751?×?10?10 to 9.8078?×?10?10 mho /m at 150°C (for x?=?0 to x?=?1). The method of synthesis and the results observed in this investigation may assist in the fabrication of optical devices when the required operational performance falls under the range observed in the study. 相似文献
Bi2Cu0.1?xAlxV0.9O5.35?x/2?δ, 0.02 ≤ x ≤ 0.08, were synthesized by standard solid-state reaction route. Structural and electrical properties of samples are characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), Fourier transform infrared (FT-IR) and alternating current (AC) impedance spectroscopy. The tetragonal γ′ phase structure is preserved to room temperature with compound x = 0.02. The stabilization of β orthorhombic phase is observed for compositions 0.04 ≤ x ≤ 0.05. As the Al content increases, the monoclinic α phase is evidenced for materials 0.06 ≤ x ≤ 0.08. The electrical investigation of Bi2Cu0.1?xAlxV0.9O5.35?x/2?δ system has been performed in the frequency range from 20 Hz to 1 MHz using AC impedance spectroscopy. The impedance spectra indicate the two semicircle arcs associated with the bulk and grain boundary resistances at temperature below ~450 ○C. The conductivity generally changes when Al is substituted. The highest conductivity at 300 ○C (σ = 2.55 × 10?4 S cm?1) is shown for x = 0.02. 相似文献
Au/silicon nitride/In0.82Al0.18As metal insulating semiconductor (MIS) capacitors were fabricated and then investigated by capacitance voltage (C–V) test at variable frequencies and temperatures. Two different technologies silicon nitride (SiNx) films deposited by inductively coupled plasma chemical vapor deposition (“ICPCVD”) and plasma enhanced chemical vapor deposition (“PECVD”) were applied to the MIS capacitors. Fixed charges (Nf), fast (Dit) and slow (Nsi) interface states were calculated and analyzed for the different films deposition MIS capacitors. The Dit was calculated to be 4.16 × 1013 cm−2 eV−1 for “ICPCVD” SiNx MIS capacitors, which was almost the same to that of “PECVD” SiNx MIS capacitors. The Dit value is obviously higher for the extended wavelength InxGa1−xAs (x > 0.53) epitaxial material as a result of lattice mismatch with substrate. Compared to the results of “PECVD” SiNx MIS capacitors, the Nsi was significantly lower and the Nf was slightly lower for “ICPCVD” SiNx MIS capacitors. X-ray photoelectron spectroscopy (XPS) analysis shows good quality of the “ICPCVD” grown SiNx. The low temperature deposited SiNx films grown by “ICPCVD” show better effect on decreasing the dark current of InxGa1−xAs photodiodes. 相似文献
Hydrogenated amorphous SiC films (a-Si1−xCx:H) were prepared by dc magnetron sputtering technique on p-type Si(1 0 0) and corning 9075 substrates at low temperature, by using 32 sprigs of silicon carbide (6H-SiC). The deposited a-Si1−xCx:H film was realized under a mixture of argon and hydrogen gases. The a-Si1−xCx:H films have been investigated by scanning electronic microscopy equipped with an EDS system (SEM-EDS), X-ray diffraction (XRD), secondary ions mass spectrometry (SIMS), Fourier transform infrared spectroscopy (FTIR), UV-vis-IR spectrophotometry, and photoluminescence (PL). XRD results showed that the deposited film was amorphous with a structure as a-Si0.80C0.20:H corresponding to 20 at.% carbon. The photoluminescence response of the samples was observed in the visible range at room temperature with two peaks centred at 463 nm (2.68 eV) and 542 nm (2.29 eV). In addition, the dependence of photoluminescence behaviour on film thickness for a certain carbon composition in hydrogenated amorphous SiC films (a-Si1−xCx:H) has been investigated. 相似文献
Four different measurement techniques: EPR, NAA, DLTS, and luminescence were applied to characterize the properties of chromium in silicon. The solubility of chromium in silicon was determined and its pairing reaction with boron was studied. The energy level atEc?0.23 eV was attributed to interstitial chromium and a second level atEv+0.27 eV was correlated to chromium-boron pairs. The luminescence band of the chromium-boron pairs was clearly identified. The properties of chromium are compared with those of other transition metal impurities in silicon crystals. 相似文献
Samples of Bi4CaxV2?xO11?(3x/2)?δ in the composition range 0.07 ≤ x ≤ 0.30 were prepared by conventional solid state reactions. The stability of different phases as a function of composition was analysed by X-ray powder diffraction, FT-IR spectra, differential thermal analysis and AC impedance spectroscopy. For the compositions x ≤ 0.10, monoclinic α-phase structure is retained at room temperature. For x = 0.13, orthorhombic β-phase is observed, whereas for x ≥ 0.17, high O2?conducting tetragonal γ-phase is stabilised. However, the highest ionic conductivity σ300°C = 3.27 × 10?4 S cm?1 was observed for x = 0.17. This higher value of conductivity of the substituted compound as compared to the parent compound can be attributed to the increased oxygen ion vacancies generated as a result of cation doping. AC impedance spectroscopy reveals the fact that this ionic conductivity is mainly due to the grain contribution. 相似文献
We used amorphous silicon oxide (a‐Si1–xOx:H) and microcrystalline silicon oxide (µc‐Si1–xOx:H) as buffer layer and p‐type emitter layer, respectively, in n‐type silicon hetero‐junction (SHJ) solar cells. We proposed to insert a thin (2 nm) intrinsic amorphous silicon (a‐Si:H) thin film between the thin (2.5 nm) a‐Si1–xOx:H buffer layer and the p‐layer to form a stack buffer layer of a‐Si:H/a‐Si1–xOx:H. As a result, a high open‐circuit voltage (VOC) and a high fill factor (FF) were obtained at the same time. Finally, a high efficiency of 19.0% (JSC = 33.46 mA/cm2, VOC = 738 mV, FF = 77.0%) was achieved on a 100 μm thick polished wafer using the stack buffer layer.