摘要:

Qualitative comparisons have been made of the effect of processing conditions on the electron trapping characteristics of SiO2using Si‐SiO2‐Al capacitors. In the presentwork, we have characterized the traps involved and studied their relationship to the processing. Four different traps have been characterized and the results indicate the smallest trap (cross section of ∼9×10−20cm2) is independent of the processing conditions. The larger traps are dependent on the processing used. The largest trap appears in the sample without the post metallization annealing treatment and has a cross section of 8×10−18cm2. The trap with cross section of 2×10−18cm2appears after post metallization annealing. The importance of these treatments explains discrepancies in the results of earlier work.

ISSN:0021-8979    

DOI:10.1063/1.329259

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Hall coefficient and dc conductivity measurements have been made in the temperature range 77–500 K on thin exptaxial films ofp‐type Pb1‐xCdxTe, grown by vacuum evaporation using a three‐temperature technique. It has been found that the principal band gap and the mobility ratio of electron to hole increases with the increase ofx. Increase ofxis found to increase Te vacancies in the films which act as donors. In the low‐temperature region, the ionised impurity scattering is found to be predominant, while the phonon scattering is found to limit the mobility of the charge carries at higher temperatures.

ISSN:0021-8979    

DOI:10.1063/1.329260

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Low‐temperature current‐voltage data for a degenerate Ge/nondegenerate GaAs (100)n‐nabrupt heterojunction grown by molecular beam epitaxy (MBE) is presented. For low reverse bias, the reverse current densityJversus voltageVis fit empirically by the relationJ= &agr;Ve−&Dgr;E/kTwith &Dgr;E= 80 meV ±10 meV and &agr; independent ofT. A model is presented which indicates that the difference between the work function of degenerate Ge and the electron affinity of GaAs is ?80 meV.

ISSN:0021-8979    

DOI:10.1063/1.329261

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A zinc oxide (ZnO) varistor subjected to a 60‐Hz voltage below the characteristic turn‐on voltage exhibits an increase in the resistive component of current with time. The rate of current increase with time can be increased with an increase in applied voltage and/or temperature. An analysis of current rise with an applied 60‐Hz voltage stress and current decay with no voltage stress data obtained for ZnO varistors indicates that the current instability phenomena is associated with the diffusion of interstitial zinc in the depletion layer regions adjacent to the ZnO‐ZnO grain boundary.

ISSN:0021-8979    

DOI:10.1063/1.329262

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Infrared elastobirefringence is used to investigate the dislocation distribution in GaAs substrates on which Ga0.35Al0.65As epitaxial layers have been grown at 950 °C using liquid phase epitaxy. A marked asymmetry is observed in the dislocation distributions as regards the two nonequivalent ⟨110⟩ directions in the (001) plane. The dislocation distributions consist mainly of 60° dislocations and a small number of pure edge dislocations. Almost all the dislocations are of the &agr; type. The dislocation distributions observed are discussed with reference to the properties of the dislocations involved and the temperature dependences of the lattice parameters of the epitaxial layer and the substrate.

ISSN:0021-8979    

DOI:10.1063/1.329263

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Barrier layers are apparently formed on Sr‐doped LaCrO3that give rise to an appreciable electrode impedance with electrodes of Au or Pt. The corresponding electrode resistance is quite sensitive to the oxygen activity in the atmosphere, following atmospheric changes at temperatures near room temperature with time constants of the order of minutes or days. The electrical properties of these barrier layers at room temperature do not conform to the models of simple Schottky layers on semiconductors, but exhibit a pattern of changing oxidation states at the interface region.

ISSN:0021-8979    

DOI:10.1063/1.329219

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

We describe a new technique for controlled oxide growth using a directed low‐energy ion beam. The technique is evaluated by fabricating Ni‐oxide‐Ni and Cr‐oxide‐Ni tunneling junctions, using oxygen ion beams with energies ranging from 30 to 180 eV. High ion current densities are achieved at these low energies by replacing the conventional dual grid extraction system of the ion source with a single fine mesh grid. Junction resistance decreases with increasing ion energy, and oxidation time dependence shows a characteristic saturation, both consistent with a process of simultaneous oxidation and sputter etching, as in the rf oxidation process. In contrast with rf oxidized junctions, however, ion beam oxidized junctions contain less contamination by backsputtering, and the quantitative nature of ion beam techniques allows greater control over the growth process.

ISSN:0021-8979    

DOI:10.1063/1.329220

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The roughness at the interface has been determined quantitatively on an atomic scale after removal of the oxide by LEED (low‐energy electron diffraction) in an ultrahigh vacuum. The energy dependant broadening of the diffracted electron beam yields the average size of step‐free terraces. Silicon (111) samples have been oxidized under various conditions concerning atmosphere (dry and wet), temperature (800 and 1000 °C), time, pretreatment, and post‐treatment. The oxidation produces a roughness, which may be decreased by low oxidation rates and appropriate annealing in nonoxidizing atmosphere. The novel technique of evaluation for the first time shows systematically how oxidation parameters determine the roughness at the interface, which again is important for the performance of metal‐oxide‐semiconductor (MOS) devices.

ISSN:0021-8979    

DOI:10.1063/1.329221

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Thick‐film resistors with Pb3Rh7015and Pb2Ru207as conductors are considered. These compounds are chemically stable during the firing process of the resistors. The variation of sheet resistivityR&laplac;with volume fraction conductor follows a simple power law. This result cannot be explained by percolation theory in its simple form. The conductivity is found to be independent of frequency up to 10 GHz. In both cases a small positive Hall coefficient is observed which is interpreted as being due to mixed electron and hole conduction. Finally the 1/fnoise is considered, and is found to vary approximately linearly withR&laplac;. A theoretical model for the 1/fnoise in thick‐film resistors is presented that accounts for this linear relationship. The observed deviations from linearity indicate that probably tunneling through barriers at the interfaces between the conducting grains is an important factor in determining the conduction.

ISSN:0021-8979    

DOI:10.1063/1.329222

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Frequency locking effects in two interacting Josephson junctions are investigated. The junctions are described in the usual resistively‐shunted‐junction (RSJ) model and coupling between junctions is provided by a resonant circuit. The system can be used to simulate interactions between superconducting weak links in a resonant cavity or via a general impedance shunt. Various types ofv‐icurves in the voltage locking region are obtained in this calculation by using a first harmonic approximation in the high‐frequency regime. Stability of order parameter phase oscillations for two identical junctions in the voltage‐locked region is examined. We also show that dissimilar junctions can be synchronized in a resonant cavity using a common series bias current.

ISSN:0021-8979    

DOI:10.1063/1.329223

出版商:AIP    

年代:1981

数据来源: AIP