摘要:

The diffusion behavior of &bgr; phase Cu–Al has been studied at 800, 850, and 950 °C using the experimental approach and analysis scheme of Kirkendall and Darken. Diffusion couples were made using the window frame technique and concentration profiles were determined by electron probe microanalysis. The chemical diffusion coefficient,D˜ was found to beD˜=0.65 exp(−42200/RT) cm2/s. The diffusivity was observed to be independent of composition over the range 11–13 wt. % Al. The self‐diffusion coefficientsDCuandDAlwere determined to beDAl=0.13 exp(−38900/RT) cm2/s andDCu=2.2 exp(−43400/RT) cm2/s. All activation energies are in calories/mole.

ISSN:0021-8979    

DOI:10.1063/1.332475

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Both GaAs and Si single crystals were laser annealed with a 20‐ns ruby laser pulse. By means of a time‐of‐flight measurement the velocity distribution and the density variation of evaporated Ga or As and Si atoms were determined for different energy densities. Simultaneously the reflectivity of the crystal surface was measured time‐resolved. The data show consistently that the molten phase occurs at energy densities ≳0.35 J cm−2for GaAs and ≳0.8 J cm−2for Si. The results are in agreement with a purely thermal model for laser annealing.

ISSN:0021-8979    

DOI:10.1063/1.332476

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A theory describing bulk better operation is presented. The theory is applicable to a diatomic gas which adsorbs dissociatively on a getter material which exhibits a time independent sticking coefficient. The theory includes the effects of surface reactions and bulk diffusion. Exact numerical solutions are presented for the particular cases of pumping and desorption. In addition, approximate analytical solutions are derived and used to illustrate the characteristics of the particular operational regimes. The theory is applied to the analysis of the pumping and desorption behavior of the Zr‐Al alloy bulk getter. The predictions of the theory are in excellent agreement with the experimentally measured Zr‐Al performance.

ISSN:0021-8979    

DOI:10.1063/1.332477

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The low resistivity and refractory nature of titanium carbide makes it potentially useful as a diffusion barrier in thin film metallization schemes. In the present investigation, deposition and properties of thin titanium carbide films have been investigated. The films were deposited by reactive radio frequency sputtering in methane–argon mixtures on a variety of substrates. The effects of methane to argon ratio, total sputtering pressure, and power on the film deposition rate, composition and properties were determined. There were interactive effects of these parameters on the composition and properties of these films. Resistivity increased with carbon content; for Ti/C≥1 it was ∼200 &mgr;&OHgr; cm. Stress that was compressive was maximum in the nearly stoichiometric TiC film. Grain size was small in all films, especially so in carbon rich films. All stoichiometric titanium carbide films were resistant to HF solutions. Films with TiC/≥1 dissolved easily in ethylene dinitrilo tetra acetric acid (EDTA) solution.

ISSN:0021-8979    

DOI:10.1063/1.332478

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The interactions of reactively sputtered titanium carbide (TixC) films with Si, SiO2, Ti, TiSi2, and Al have been studied using Auger electron spectroscopy, x‐ray diffraction, and four‐point probe resistance. The TixC films react with Si leading to silicide phases that are not observed when pure Ti reacts with Si. The interaction of TixC with Si is delayed to higher temperatures with increasing carbon content. Forx≤1, no interaction is observed even after 900 °C‐30 min anneal. Forx≥1, the silicide formation leads to phase separation with TiSi2near the silicon substrate plus an outer titanium carbide layer, which, like all other TixC films investigated, is found to be an effective diffusion barrier to Al penetration up to 500 °C. Forx≤1, no interaction with SiO2is observed up to 900 °C. However, Ti‐rich films interact with SiO2to form titanium oxide. The stoichiometric film adheres to Ti and TiSi2much better than to Si and SiO2. It does not react with Ti or TiSi2up to 750 °C. At 900 °C TiC is unstable on TiSi2.

ISSN:0021-8979    

DOI:10.1063/1.332479

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The luminescence data of Schmid, Thewalt, and Dumke on heavily dopedp‐type Si has been analyzed to provide the effective band gap for then⋅pproduct at room temperature inp+Si. The results are in very good agreement with the measurements of Slotboom and DeGraaff, and extend the acceptor concentrations for which the effective band gap is available by a factor of four. The disagreement of these results with the values obtained from infrared absorption measurements is further evidence of a nonrigid band‐gap shift.

ISSN:0021-8979    

DOI:10.1063/1.332480

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Copper‐diffused InP and GaAs have been studied using junction space‐charge spectroscopy. Two dominant copper‐related deep level defects are observed in both materials. Photoionization cross sections of holes and electrons, thermal hole emission rates, and one electron capture cross section have been measured. In InP one of the ionization spectra exhibits a pronounced phonon‐related structure. The results, together with previous work on GaAs:Cu, GaP:Cu, GaAs:Cu, and AlGaAs:Cu, indicate a common geometrical structure for each of the two copper‐related defects in all the materials.

ISSN:0021-8979    

DOI:10.1063/1.332481

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Deep level hole‐(Ev+0.39 eV) and electron‐trapping (Ec−0.34 eV) centers associated with oxygen ion implanted at 1 MeV (1014ions cm−2) have been detected in Schottky barrier germanium diodes by deep level transient spectroscopy, following thermal anneals under molecular hydrogen. No traps were present after heating under atomic hydrogen from a radiofrequency induced plasma, indicating passivation by hydrogenation. Drift of the peaked, electron trap distribution formed at the projected ion range was observed across the depletion layer of a reverse biased Schottky diode with an average mobility of 5.5±1×10−15cm2 V−1 s−1at 25 °C.

ISSN:0021-8979    

DOI:10.1063/1.332482

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The effect of pressure on the band gap and flatband potential ofn‐ andp‐type InP and GaAs was studied to 10 kbar at 300 K. For both InP and GaAs it was determined that the increase of the energy gap of the direct transition is to first order due to an increase in energy of the conduction band edge.

ISSN:0021-8979    

DOI:10.1063/1.332483

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A calculation is presented to describe the modification of the carrier distribution due to the presence of high‐intensity CO2laser radiation for several semiconductors. In the calculation the intercarrier collision rates are assumed to be sufficiently large that the distribution can be described by a carrier temperature, which may be much larger than the lattice temperature. The steady‐state carrier temperature is calculated as a function of the light intensity by equating the rate of energy which the carriers receive from the electromagnetic field and the rate of energy which the carriers lose to the lattice by the emission of phonons. For sufficiently high light intensities, a significant fraction of the total free carrier density can have kinetic energies which exceed the band gap. These hot carriers are energetically capable of relaxing by undergoing an inelastic pair‐producing scattering event. This impact ionization process can lead to the formation of a laser‐induced plasma by the absorption of light well below the band gap of the material. Explicit values are presented for the intensity thresholds at which the impact ionization process becomes important for light in the 9–11 &mgr;m region. Comparison of the results with transmission measurements indicate that this mechanism may be responsible for the nonlinear absorption observed in several semiconductors by high‐intensity pulsed CO2laser light.

ISSN:0021-8979    

DOI:10.1063/1.332484

出版商:AIP    

年代:1983

数据来源: AIP