摘要:

We have investigated the formation of polycrystalline TiN films on (100) Si substrates using a low‐temperature laser processing method. The films were deposited by laser ablation of a TiN hot‐pressed pellet in the presence of neutral or ionized nitrogen using a XeCl excimer laser (wavelength 308 nm, pulse duration 45×10−9s, and energy density of 4–5 J cm−2). The substrate temperature ranged from 25 to 550 °C. Plan‐view and cross‐section transmission electron microscopy studies show that the films are polycrystalline (average grain size ∼100 A˚) with face‐centered‐cubic structure and lattice constant of 4.25 A˚. It is interesting to note that the average grain size remained approximately constant with substrate temperature up to 550 °C. Chemical composition was analyzed by Rutherford backscattering and Auger electron spectroscopy as a function of film depth. The results show that the films reproduced closely the chemical composition of the TiN target which contained some oxygen, and that the oxygen content decreased with increased substrate temperature. Four‐point probe measurements andI‐Vcharacteristics show that the films are metallic with a typical resistivity of ∼150 &mgr;&OHgr; cm. The microhardness values of these films were found to be as high as 17 GPa.

ISSN:0003-6951    

DOI:10.1063/1.101338

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Low‐temperature photoluminescence measurements in undoped Ga1−xAlxAs (0≤x≤0.32) and GaAs/GaAlAs quantum structures grown by molecular beam epitaxy are performed before and after hydrogen plasma exposure. In both cases we observe a strong enhancement of the luminescence after the exposure. In the GaAlAs epilayers this enhancement clearly depends on the Al concentration in the alloy. The results are explained in terms of passivation of nonradiative traps in the GaAlAs that increases the carriers’ lifetime and diffusion length allowing, in the case of the multilayers, a greater number of carriers to recombine in the quantum well.

ISSN:0003-6951    

DOI:10.1063/1.101339

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A simple two‐terminal method is described for the determination of generation lifetime in intrinsic polycrystalline silicon suitable for thin‐film transistor applications using a metal/SiO2/polycrystalline silicon/n‐type silicon test structure. The method consists of monitoring the high‐frequency capacitance of the test structure after the application of a voltage pulse of the correct polarity to cause deep depletion in then‐type substrate. Generation lifetimes of 34 ps to 19 ns are obtained for polycrystalline silicon films of varying grain size.

ISSN:0003-6951    

DOI:10.1063/1.101340

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We investigate several silicide/silicon Schottky barrier heights under hydrostatic pressures up to 10 kbar. The barriers of polycrystalline TiSi2, PtSi, and WTi onn‐type Si decrease with −1.l3, −1.35, and −1.42 meV/kbar, respectively. The coefficients forA‐ andB‐type NiSi2/Si amount to −0.77 and −0.89 meV/kbar and are too small to support models which ascribe the l40 meV barrier difference of these two types to different interface bond lengths. The pressure coefficients are, on the other hand, within a range of predictions of Cardona and Christensen which are based on pure bulk properties.

ISSN:0003-6951    

DOI:10.1063/1.101385

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The use of an I+2and I+primary ion beam in secondary‐ion mass spectrometry measurements was studied to investigate its depth profiling properties. A comparison with the results of a Cs+, O+2, and O+primary beam was made. Experiments were performed with low impact energy (down to 1.7 keV) and glancing angle of incidence on molecular beam epitaxy AlGaAs‐GaAs multilayer structures. The best obtainable decay length of the Al+signal with an iodine primary beam is 1.1 nm. At low impact energies, no mass dependence on the depth resolution is observed. In these conditions, a useful yield for Al+of approximately 5×10−5was obtained with the Cs+beam and 10−2with the iodine and oxygen beams.

ISSN:0003-6951    

DOI:10.1063/1.101341

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Ion implantation (i/i) technology is employed for silicon trench sidewall doping. The aspect ratio of trenches for high Mbit DRAM is very large (depth/width≥10), so that very small glancing‐angle i/i to sidewalls is necessary. In this case, reflected ions are large in number and are implanted to the opposite sidewall. It is very important to know the elemental depth profile in the opposite sidewall to understand the implantation mechanism. For the first time, we measured the depth profiles at several positions of the opposite trench sidewall by secondary‐ion mass spectroscopy for arsenic and boron ion implantations. It is found that reflected ions are distributed near the facing region of the directly implanted region with smaller energies than the primary energy. These findings are compared with the simulations based on themarloweprogram.

ISSN:0003-6951    

DOI:10.1063/1.101342

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The use of ethylene (C2H4) rather than methane (CH4) as the source of carbon in the hydrogenated amorphous silicon carbide (a‐SiC:H)p+layer of hydrogenated amorphous silicon (a‐Si:H) based solar cells deposited in a glow discharge has been explored. Device results are presented to demonstrate the utility of ethylene‐baseda‐SiC:H for use in thep+layer. Device results and material measurements reveal that the use of ethylene under the proper conditions can yieldp+a‐SiC:H which has optical and transport properties which are at least as suitable as methane‐based material.

ISSN:0003-6951    

DOI:10.1063/1.101343

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Oxygen implanted at a concentration above that of the acceptors inp‐type GaAs is shown to create thermally stable, high‐resistivity material only in the case of Be doping in the GaAs. The effect is not seen for Mg, Zn, or Cd doping. Similarly, there is no apparent interaction of O withn‐type dopants (S or Si) in our measurements. The Be‐O complex inp‐type GaAs is a deep donor, creating material whose sheet resistivity shows an apparent thermal activation energy of 0.59 eV for a structure involving a thin layer (5000 A˚) of oxygen compensated, Be‐doped GaAs on a semi‐insulating substrate.

ISSN:0003-6951    

DOI:10.1063/1.101344

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Fine lines of 1.5‐&mgr;m‐wide and 80‐nm‐thick Co were patterned by a lithographic technique and deposited by electron gun onto (100) Si surfaces. Reacting the Co and Si to form CoSi2lines was carried out at 600 °C in He atmosphere. The composite surface consisting of alternating silicides and Si as seen by scanning electron microscopy showed qualitatively that the silicide lines have sunk completely into the Si and the entire surface appears planar. Quantitative changes in vertical direction before and after the formation of the silicide lines have been measured by atomic force microscopy.

ISSN:0003-6951    

DOI:10.1063/1.101386

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The low‐temperature properties of the interface photoluminescence emission in GaxIn1−xAs‐InP single heterojunctions grown by molecular beam epitaxy are investigated with changes of temperature and excitation intensity at different depths across the interface. The emission energy shifts to higher energy with increasing excitation intensity and lies between the three‐dimensional GaxIn1−xAs‐InP near‐band‐edge exciton and the quasi‐donor–acceptor pair transition. The new emission is attributed to the interface exciton which is indirect in real space.

ISSN:0003-6951    

DOI:10.1063/1.101325

出版商:AIP    

年代:1989

数据来源: AIP