摘要:

In double‐layered tantalum silicide/phosphorus‐doped silicon films, the resistivity of silicon can increase sharply by high‐temperature annealing. The increase depends on grain boundaries in the silicon films, and annealing ambient. It is not affected by the extent of interface reaction or diffusion, or the type of silicide used. A decrease in phosphorus content is due to phosphorus out diffusion from the silicon films, as determined by secondary ion mass spectrometry.

ISSN:0734-211X    

DOI:10.1116/1.582535

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

The early stage of silicide formation was studied by depositing Si on W tip specimens of the FIM and the atom probe. The optimum temperature for W silicide formation was found to be 900–1000 K and its composition was WSi2. The observed FIM image of the silicide agreed well with the computer‐simulated image which was composed of the W atoms of the tetragonalC11bstructure. The silicide often grew independently on each W{001} plane because the W lattice constant of these planes matches well with that of the basal plane of the silicide. The boundary between the independently grown silicides was also observed along the expected areas from the simulated image.

ISSN:0734-211X    

DOI:10.1116/1.582506

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

Silicon‐deposited Ni tips were heated at various temperatures up to 1000 K and structures and compositions of thin Ni silicide layers formedinsituwere investigated by the atom probe and the field ion microscope (FIM). Although a mixed layer of Ni and Si was formed even at 80 K, FIM images of an ordered silicide structure were observed after heating the tip above 900 K. It was noticed that the evaporation field of the ordered silicide is significantly higher than those of Ni and Si, possibly due to a strong binding force among the constituting atoms. Since Ni is the major moving species, the Ni concentrations in the thin silicide layers were found to be as high as Ni4Si near the surface and decreased to NiSi at the boundary of the silicide and the substrate Ni. Although the composition of the silicide, which showed the ordered image, changed from Ni5Si2to NiSi as the mass analysis was proceeded from the surface of the silicide to the substrate Ni, the silicide consistently exhibited the FIM image which was characteristic of a cubic structure. The computer‐simulated image of the hypothetical structure for the observed silicide, a modified cubicC1 structure, showed the characteristic features of the observed silicide image.

ISSN:0734-211X    

DOI:10.1116/1.582533

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

Polysilicides currently find great interest as low resistivity gate and interconnect materials for integrated MOS circuits. We report on detailed investigations of the dry etching characteristics of Ta–silicide/n+‐poly‐Si double layers in fluorine and chlorine containing gases. A batch‐type parallel plate reactor operated in RIE mode is used. We find a sensitive dependence of the etching results on various process parameters, such as gas mixtures, pressure, and rf power. Possible mechanisms for these findings are discussed. Anisotropic etching of the double layer has been achieved using a two stage process. In addition, we analyze the influence of the layer preparation technique on etching profiles.

ISSN:0734-211X    

DOI:10.1116/1.582534

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

A recent review of plasma etching is extended with discussions of similarity variables governing discharges, anisotropic oxide etching in fluorine and unsaturate‐rich plasmas, surface texture, the loading effect, and gas‐surface reactions.

ISSN:0734-211X    

DOI:10.1116/1.582536

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

Argon sputter etching of single crystal Si results in damage of the surface and entrapment of the sputtering gas. In a 6‐kV dc sputtering system these effects have been observed and characterized by Rutherford backscattering. Irradiation by a Q‐switched ruby laser was found to restore the crystal quality and to release the entrapped gas.

ISSN:0734-211X    

DOI:10.1116/1.582538

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

An argon ion beam is combined with a Cl2gas jet to etch silicon. Auger electron spectroscopy is used to measure the surface coverage of chlorine simultaneous with the etch process. This steady state surface chlorine coverage is enhanced by an increase in the Cl2flux or a decrease in Ar ion flux. The coverage varies from 10% to 100% of saturation as the Ar+to Cl2flux ratio varies from 0.4 to 0.004. The Si etch rate increases with increasing Cl2flux giving an enhancement of as much as a factor of 3 over pure Ar+sputtering at 500 eV. A general model is presented which is based on the mass balance of ionic and neutral species to and away from the surface region. Assumptions are made to apply the model to the Ar++Cl2+Si system. Expressions for both the surface Cl coverage and silicon etch rate are then obtained as functions of the incident Ar+and Cl2fluxes. The model is fit to the data and accounts for all of the observed trends in surface coverage and etch rate.

ISSN:0734-211X    

DOI:10.1116/1.582539

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

Thermally grown SiO2layers on Si were bombarded with He+, Ar+, and Xe+ions at energies between 0.5 and 2 keV and subsequently studied by XPS. Chemical shifts of the Si 2pand O 1speaks were not observed as a result of sputtering. Apparently, the oxide is not reduced by ion bombardment. However, the widths of the Si 2pand O 1speaks increase with ion dose and ion energy. A steady state peak width was obtained at each energy for ion doses above 2×1017cm−2. Steady state peak width dependence on ion species and energy is explained by a model based on the mean‐projected ion range. Peak broadening can be explained by an increase in disorder that results from changes in the Si–O bond angle distribution within the ion range.

ISSN:0734-211X    

DOI:10.1116/1.582540

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

Anodic dissolution and passivation characteristics ofn‐ andp‐type III‐V compounds (III=Ga, In and V=P, As, Sb) have been compared in aqueous electrolytes. A range of interfacial behavior was observed on controlled potential cycling of these semiconductors in acidic, basic, and neutral solutions, the differences being more pronounced in acids. The dissolution of InP on anodization is severely inhibited even in acid medium by the formation of a coherent film removable only by extensive cathodic reduction. GaP, InSb, and GaSb passivate less readily, forming solubility‐limited precipitates on the surface at high current densities. Passivation of InAs or GaAs atpH∼0 is virtually unreachable, except at extremes of current densities, with the films formed being quite porous and permitting considerable surface corrosion. The gradation of properties observed in the III–V compound series indicates that both group III and V members are involved in the film formation. Previous observations of the functions of films on InP and GaAs in photoelectrochemical cells, in acid and neutral media, respectively, are consistent with the above results. The formation of indium layers in InP, after reduction in acid media, has been demonstrated by ring–disk electrode techniques.

ISSN:0734-211X    

DOI:10.1116/1.582541

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

The step coverage of undoped and phosphorous‐doped SiO2glass films has been studied. Various parameters which play a role in determining the quality of the step coverage are briefly discussed. The step coverage capability of various deposition processes is evaluated. The processes compared are: atmospheric‐pressure CVD, low‐temperature, low‐pressure CVD (Silox), mid‐temperature, low‐pressure CVD (TEOS) and plasma‐enhanced CVD. The parametric dependence of the step coverage obtained in the deposition of undoped glass by use of the mid‐temperature low‐pressure technique is reported. It is demonstrated that the quality of the step coverage is strongly dependent on the deposition conditions. It improved with increasing TEOS flow rate and molecular residence time in the reactor. Addition of nitrogen, oxygen, or phosphine/nitrogen mixture to the TEOS causes a deterioration in the step coverage capability of the deposition process. The step coverage of this particular process is independent of the deposition temperature in the range 650–780 °C.

ISSN:0734-211X    

DOI:10.1116/1.582542

出版商:American Vacuum Society    

年代:1983

数据来源: AIP