摘要:

An infrared absorption spectrum has been obtained for the shallowA2acceptor level formed by neutron irradiation of Si:Ga. After a 600 °C anneal, absorption peaks were observed at 213.1, 244.9, and 286.9 cm.−1These peaks appear to correspond to lines 1, 2, and 4 of a group III‐like acceptor spectrum originating from a ground state with a 40.4‐meV binding energy. Hall effect measurements confirm the presence of an acceptor level at this energy.

ISSN:0003-6951    

DOI:10.1063/1.95156

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

We describe the use of a wide‐area (38 cm2) electron beam as a heat source to interdiffuse 400‐A˚‐thick sputter‐deposited titanium films into 3–6‐&OHgr; cm⟨100⟩n‐type silicon wafers. Isochronal exposures of 30 s with electron beam of current densities greater than 250 mA/cm2reduced the as‐deposited sheet resistance by a factor of 10, while exposures at half this current caused the sheet resistance to increase by a factor of 2.5. Compositional depth profiles obtained from a combination of ion beam sputtering and Auger electron spectroscopy show that this resistivity increase is caused by diffusion of oxygen into the titanium film induced by the electron beam heating. At exposures to beam intensities sufficient to induce complete silicide formation, oxygen is segregated at the surface by the advancing silicon. We conclude that the silicide self‐cleanses itself of oxygen during formation.

ISSN:0003-6951    

DOI:10.1063/1.95157

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Amorphous silicon staggered‐electrode thin‐film transistors (TFT’s) can show current crowding near the origin in the output characteristics. The degree of current crowding is governed by the voltage dependence of the current flowing from then+contact to the conducting channel. This current is a space‐charge‐limited current whose magnitude depends on the bulk density of states in the undoped intrinsic layer. For a 0.5‐&mgr;m‐thickilayer, calculations predict negligible current crowding forN(E)<1016cm−3 eV−1, but severe current crowding forN(E)>3×1016cm−3 eV−1. Experimental results are consistent withN(E) in the range 1016cm−3 eV−1–2×1016cm−3 eV−1. This is lower than the value derived from the transfer characteristic of the TFT (∼1017cm−3 eV−1), which is evidence for an inhomogeneous distribution of deep gap states through the 0.5‐&mgr;m film of &agr;‐Si:H.

ISSN:0003-6951    

DOI:10.1063/1.95158

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

High resolution core level photoemission spectroscopy has been used to obtain the first direct identification of the chemical species remaining on silicon surfaces after exposure to fluorine. Both Si(111) 2×1 and Si(111) 7×7 were exposed to fluorine via the dissociative chemisorption of XeF2. For fluorine coverages in the monolayer regime, SiF1, SiF2, and SiF3were all present although their relative abundance varied significantly between the two surfaces. No evidence for the existence of unreacted interestitial fluorine was found. These results suggest the need for modification of current models describing plasma and reactive ion etching of silicon.

ISSN:0003-6951    

DOI:10.1063/1.95159

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Single‐crystal Si samples with nitrogen (N) impurities (Si:N) and with N and phosphorus (P) impurities (Si:N:P) have been investigated by electron spin resonance measurements. It was found that substitutional N impuritiesNscannot be incorporated into Si by cw laser annealing of N ion‐implanted Si or by N doping during crystal growth; however,Nsis incorporated into Si by pulsed‐laser annealing (PLA) of N ion‐implanted Si. The spin density ofNsdecreases with doping of P shallow donors into PLA Si:N and increases by introduction of slight point defects in PLA Si:N:P. These results suggest thatNswith a negative charge are formed in PLA Si: N:P system.

ISSN:0003-6951    

DOI:10.1063/1.95160

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Charge transfer doping of amorphous silicon by amorphous silicon nitride is demonstrated in amorphous semiconductor superlattice structures. The transfer‐doped material has lower gap‐state density and higher photoconductivity than conventional substitutionally doped material.

ISSN:0003-6951    

DOI:10.1063/1.95161

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A perturbation method is used to calculate the change of the total zero‐voltage current &Dgr;Ic(y0) flowing through a one‐dimensional Josephson tunnel junction due to a focused laser beam irradiated aty0. Nonlocal response of the phase difference function &fgr; as well as the local response of the  amplitudeJto the laser beam are included. In the junction configuration we considered, it is found that the nonlocal effect can, depending upon the external magnetic field, make the spatial dependences of &Dgr;Ic(y0) and the current distribution different.

ISSN:0003-6951    

DOI:10.1063/1.95162

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The effective interdiffusion coefficient of metallic bilayers under ion irradiation has been correlated with the heat of mixing of corresponding binary alloys. The results are interpreted according to Darken’s theory of chemically enhanced diffusion.

ISSN:0003-6951    

DOI:10.1063/1.95163

出版商:AIP    

年代:1984

数据来源: AIP