Effect of thermal treatment on the characteristics of iridium Schottky barrier diodes on n-Ge (1 0 0)

Iridium (Ir) Schottky barrier diodes were deposited on bulk grown (100) Sbdoped n-type germanium by using the electron beam deposition system. Electrical characterization of these contacts using current-voltage (I-V) and capacitance-voltage (C-V) measurements was performed under various annealing conditions. The variation of the electrical properties of these Schottky diodes can be attributed to combined effects of interfacial reaction and phase transformation during the annealing process. Thermal stability of the Ir/n-Ge (100) was observed up to annealing temperature of 500oC. Furthermore, structural characterization of these samples was performed by using a scanning electron microscopy (SEM) at different annealing temperatures. Results have also revealed that the onset temperature for agglomeration in a 20 nm Ir/n-Ge (100) system occurs between 600-700oC.This work has been made possible by financial assistance from the South African National Research Foundation.http://www.elsevier.com/locate/jallcomnf201

Characterization of defects created in Cz and epitaxial Si doped with Ga or B using Laplace-DLTS

We have measured the electrical and annealing properties of defects created in epitaxial and Czochralski-grown Si doped with either B or Ga by electron irradiation using both conventional and Laplace deep level transient spectroscopy (L)-DLTS. With L-DLTS, we have been able to resolve several defects that cannot be resolved using conventional DLTS. L-DLTS provides a new avenue to study defect introduction rates and annealing kinetics in B- and Ga-doped Si. The isochronal annealing behaviour of the defects was also investigated

Annealing and surface conduction on Hydrogen peroxide treated bulk melt-grown, single crystal ZnO

We report on the studies carried out on hydrogen peroxide treated melt-grown, bulk single crystal ZnO samples. Results show the existence of two shallow donors in the as-received ZnO samples with energy levels (37.8±0.3) meV that has been suggested as Zni related and possibly H-complex related and (54.5±0.9) meV, which has been assigned to an Al-related donor. Annealing studies performed on the hydrogen peroxide treated samples reveal the existence of a conductive channel in the samples in which new energy levels have been observed, Zn vacancies, related to the Group I elements, XZn. The surface donor volume concentration of the conductive channel was calculated from a theory developed by Look (2007) [1]. Results indicate an increase in the surface volume concentration with increasing annealing temperature from 60×1017 cm−3 at 200 °C to 4.37×1018 cm-3 at 800 °C

Effect of thermal treatment on the characteristics of iridium Schottky barrier diodes on n-Ge (1 0 0)

Iridium (Ir) Schottky barrier diodes were deposited on bulk grown (1 0 0) Sb-doped n-type germanium by using the electron beam deposition system. Electrical characterization of these contacts using current–voltage (I–V) and capacitance–voltage (C–V) measurements was performed under various annealing conditions. The variation of the electrical properties of these Schottky diodes can be attributed to combined effects of interfacial reaction and phase transformation during the annealing process. Thermal stability of the Ir/n-Ge (1 0 0) was observed up to annealing temperature of 500 °C. Furthermore, structural characterization of these samples was performed by using a scanning electron microscopy (SEM) at different annealing temperatures. Results have also revealed that the onset temperature for agglomeration in a 20 nm Ir/n-Ge (1 0 0) system occurs between 600 and 700 °C

Characterization of the E(0.31) defect introduced in bulk n

Bulk antimony (Sb) doped germanium (n-Ge) samples with doping concentrations ranging between 7.0 1014 cm 3 and 2.5 1015 cm 3 were exposed to a dc-hydrogen or helium plasma. Hydrogen exposure resulted in the introduction of a single prominent defect level at EC 0.31 eV. Exposing similar samples to He plasmas introduced the same electron trap. The trap concentration increased linearly with dopant concentration suggesting that Sb may be a component of this plasma-induced trap. Thermal annealing kinetics studies suggested that this defect anneals out by diffusion.http://jap.aip.org/nf201

Deep level transient spectroscopy (DLTS) study of defects introduced in antimony doped Ge by 2 MeV proton irradiation

Deep level transient spectroscopy (DLTS) and Laplace-DLTS have been used to investigate the defects created in Sb doped Ge after irradiation with 2 MeV protons having a fluence of 1×1013 protons/cm2. The results show that proton irradiation resulted in primary hole traps at EV +0.15 and EV +0.30 eV and electron traps at EC −0.38, EC −0.32, EC −0.31, EC −0.22, EC −0.20, EC −0.17, EC −0.15 and EC −0.04 eV. Defects observed in this study are compared with those introduced in similar samples after MeV electron irradiation reported earlier. EC −0.31, EC −0.17 and EC −0.04, and EV +0.15 eV were not observed previously in similar samples after high energy irradiation. Results from this study suggest that although similar defects are introduced by electron and proton irradiation, traps introduced by the latter are dose dependent.South African National Research Foundation and Monash University, South Afric

The dependence of barrier height on temperature for Pd Schottky contacts on ZnO

Temperature dependent current–voltage (I–V) and capacitance–voltage (C–V) measurements have been performed on Pd/ZnO Schottky barrier diodes in the range 60–300 K. The room temperature values for the zero bias barrier height from the I–Vmeasurements (ΦI–V) was found to be 0.52 eV and from the C–V measurements (ΦC–V) as 3.83 eV. From the temperature dependence of forward bias I–V, the barrier height was observed to increase with temperature, a trend that disagrees with the negative temperature coefficient for semiconductor material. The C–V barrier height decreases with temperature, a trend that is in agreement with the negative temperature coefficient of semiconductor material. This has enabled us to fit two curves in two regions (60–120 K and 140–300 K). We have attributed this behaviour to a defect observed by DLTS with energy level 0.31 eV below the conduction band and defect concentration of between 4×1016 and 6×1016 cm−3 that traps carriers, influencing the determination of the barrier height

Comparison of nickel, cobalt, palladium, and tungsten Schottky contacts on n-4H-silicon carbide

We have investigated the current-voltage (I-V) characteristics of nickel (Ni), cobalt (Co), tungsten (W) and palladium (Pd) Schottky contacts on n-type 4H-SiC in the 300–800 K temperature range. Results extracted from I-V measurements of Schottky barrier diodes showed that barrier height (ФBo) and ideality factor (n) were strongly dependent on temperature. Schottky barrier heights for contacts of all the metals showed an increase with temperature between 300 K and 800 K. This was attributed to barrier inhomogeneities at the interface between the metal and the semiconductor, which resulted in a distribution of barrier heights at the interface. Ideality factors of Ni, Co and Pd decreased from 1.6 to 1.0 and for W the ideality factor decreased from 1.1 to 1.0 when the temperature was increased from 300 K to 800 K respectively. The device parameters were compared to assess advantages and disadvantages of the metals for envisaged applications.The Midlands State University and University of Pretoria.http://www.elsevier.com/locate/physb2019-04-15hj2017Physic