摘要:

The use ofQ‐switched ruby laser and multiscanning electron‐beam annealing to produce the reaction of thin Ti and Ni films deposited onto silicon single crystals has been studied. Rutherford Backscattering (RBS),16O(d, p)17O* nuclear reaction, scanning electron microscopy (SEM) observation, and x‐ray diffraction were used to characterize the reacted layers. It was found that laser annealing produces a reaction only at the metal‐semiconductor interface: the reacted layers are not uniform in composition and more similar to a mixture than to a well‐defined phase. On the contrary, the silicide layers produced by multiscanningebeam result from the solid‐state reaction of the whole metal film and have a layered structure with well‐defined phase composition and sharp interfaces both between the silicide phases and the underlying semiconductor in Ti/Si system. It was observed that the TiSi2growth mechanism duringeirradiation cannot be explained with the parabolic ’’diffusion controlled’’ mechanism operating in the standard furnace annealing. All our observation seems to indicate that the growth mechanism is a ’’nucleation controlled’’ process, in which the growth speed of the disilicide is limited by the speed of ejection of oxygen from a TiSi2layer. In a Ni/Si system, only the NiSi phase could be obtained as a very uniform layer after thee‐beam irradiation; the impossibility of obtaining the Ni2Si phase indicates that, in these conditions, the ’’first‐phase nucleation law’’ is no more valid.

ISSN:0021-8979    

DOI:10.1063/1.330651

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Growth of epitaxial (Al,Ga)As/Al/(AlGa)As by molecular beam epitaxy was not found successful. Thermal expansion coefficient mismatch between Al and GaAs and reduction of Al melting point by partial dissolution of incident Ga and As species and with species diffusing across the metal‐semiconductor interface, make epitaxial (AlGa)As growth on Al above ∼300 °C impossible. Below ∼200 °C GaAs tends to be polycrystalline. Even below 480 °C GaAs becomes semi‐insulating by high deep level concentrations.

ISSN:0021-8979    

DOI:10.1063/1.330652

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

A simple formula for stress produced by differential thermal contraction in a multilayered structure composed of thin layers on a thick substrate is derived. Formulas for bending radius and substrate stress are also given. Numerical results agree with more complicated calculations of prior work.

ISSN:0021-8979    

DOI:10.1063/1.330653

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Cadmium and zinc compositions in Cu2S formed on ZnxCd1−xS films (0<x≲0.25) by means of ion exchange have been measured using Auger Electron Spectroscopy (AES), Atomic Absorption Spectroscopy (AAS), and Electron Spectroscopy for Chemical Analysis (ESCA). Net concentrations of Cd and Zn in as‐formed Cu2S are generally in the 1018–1019cm−3range. Heat treatments in both oxidizing and reducing ambients raise the concentrations by over an order of magnitude, with the Zn concentrations increasing more so than those of Cd. Large increases in Zn at or near the Cu2S surface were measured subsequent to heat treatment, accompanied by increased oxygen. Following heat treatments, Cd and Zn concentrations in the Cu2S ’’bulk’’ are found to be less than 1019and 1020cm−3, respectively, for all substrate compositions used.

ISSN:0021-8979    

DOI:10.1063/1.330654

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Two techniques have been examined for the direct measurement of minority carrier capture cross sections of deep‐lying impurity states in silicon. Both involved the use of a bipolar transistor structure with which minority carrier flow through the device could be controlled. In one technique the carrier capture transient due to the flow of this minority current was directly monitored, and in the other case the current was simply used to empty centers in the minority carrier half of the band gap of majority carriers prior to employing the conventional diode short‐circuit technique. It was shown by the former technique that the capture cross sections of gold and platinum in silicon are strongly field dependent. In addition, some evidence is presented to suggest that the donor and acceptor levels of platinum in silicon may not be different charge states of the same center. Data are reported on the temperature dependence of the minority carrier cross sections of gold and platinum in silicon. Lifetime measurements in gold‐killed diodes were found to be within a factor of two of the lifetime values calculated using the measured capture cross sections.

ISSN:0021-8979    

DOI:10.1063/1.330655

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The theoretical behavior of both the photomagnetoelectric (PME) effect short‐circuit currentIPMEand the photoconductance &Dgr;Gis studied as a function of the light intensity, for any injection level. This is carried out by assuming that in a semiconductor band gap, there are two energy levels which control the recombination kinetics. Also, the dependence of bothIPMEand &Dgr;Gon the light intensity is studied as a function of the illuminated surface recombination velocity.

ISSN:0021-8979    

DOI:10.1063/1.330656

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The charge carrier transport in a solar cell is studied taking into account the dependence of the minority carrier lifetime on the injection level. The nonlinear continuity equation so obtained is solved by using a perturbative method. The spectral response of a silicon solar cell at high light intensity is evaluated on the basis of the proposed model. Theoretical results agree very well with some recently reported experimental data, for silicon solar cells at high intensity. However, there is evidence that in the light intensity range where our perturbative approach can be applied, the effect of the nonconstant minority carrier lifetime on the total short circuit current of the solar cell is quite small.

ISSN:0021-8979    

DOI:10.1063/1.330657

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Tunnel junctions using a barrier of amorphous silicon (a‐Si) between normal and superconducting metals were studied at temperatures from 300 to 0.45 K. These junctions were reliably made by depositing on a 77 K glass substrate Ni or Au,a‐Si 60 to 100 A˚ thick, and then Al. It was demonstrated that the dominant conduction process was elastic tunneling by the presence of structure caused by the superconducting energy gap of Al, and by comparing measurements of the voltage, temperature, and barrier thickness dependence of the conductance with theory. The effective barrier heights were grouped close to 2×10−2eV. A semiquantitative argument suggests that the barriers controlling the elastic tunneling are much the same as those controlling the phonon‐activated variable range tunneling at higher temperatures. Althougha‐Si barriers can be formed reliably and have low leakage, the low barrier height leads to large nonlinearity even at low voltages.

ISSN:0021-8979    

DOI:10.1063/1.330658

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The influence of redox couples on the measured flatband potentials ofn‐CdSe was investigated. It is concluded that flatband shifts are due to interface surface state‐redox electrolyte carrier exchange that leads to variable interface state charge. Interface state densities ∼2×1012cm−2, were determined with thin anodically grown selenium layer. A band diagram for the CdSe/Se electrode is presented.

ISSN:0021-8979    

DOI:10.1063/1.330659

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The contact reaction of a Si substrate with codeposited Pd‐W and Pt‐W alloy films has been compared to that with codeposited Pd‐Si and Pt‐Si alloy films. Effects of alloy composition and heat treatment on component redistribution, reaction product, temperature of silicide formation, and morphological changes have been analyzed by ion backscattering, x‐ray diffraction, and scanning electron microscopy and correlated with earlier current‐voltage measurements of change of Schottky barrier height. The advantage and disadvantage of using alloys of near noble and refractory metals and of using alloys of near noble metal and Si for the formation of shallow contacts of high Schottky barrier height (0.87–0.74 eV) are reviewed.

ISSN:0021-8979    

DOI:10.1063/1.330660

出版商:AIP    

年代:1982

数据来源: AIP