摘要:

Unhydrogenated diamond‐like carbon films were prepared at room temperature by a simple dc plasma chemical vapor deposition system with a low overall power consumption. A gaseous mixture of methane and argon (1:9) was used as a material gas with the intent of bombarding the growing film with Ar+ions. The bombardment of the depositing species with Ar+ions present in the plasma leads to (i) removal of hydrogen from the carbon atoms and (ii) a preferential resputtering of weakly bonded graphite precursors from the film surface giving rise to diamond‐like properties of the films. The progressive thermal annealing of the films induces graphitization, and promotes growth of the crystallites at higher anneal temperatures (≥500 °C)

ISSN:0003-6951    

DOI:10.1063/1.105073

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A novel microscopic method, based on the technique of laser‐induced transient reflecting gratings, is proposed to monitor ion implantation in silicon by noncontact and nondestructive ways. Some unique advantages of this technique, such as high sensitivity to ion dose and potential real time imaging capability, are demonstrated.

ISSN:0003-6951    

DOI:10.1063/1.105074

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Oxygen gettering to dislocations slows and stops dislocation motion caused by applied stress in silicon crystals. A model is presented that quantitatively describes the inhibition of dislocation motion by accounting for the drag caused by the oxygen atmosphere in the crystal around the dislocation and for oxygen aggregates inside the dislocation core. The oxygen distribution is computed by analysis of diffusion and stress‐assisted migration in the crystalline lattice. The predictions of the model agree quantitatively with the experimental data of Imai and Sumino. Hysteresis is predicted in the dependence of the dislocation velocity on applied stress and explains the difference in the unlocking and locking stresses for dislocation motion.

ISSN:0003-6951    

DOI:10.1063/1.105241

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The elastic strain in Al‐0.5% Cu metal lines under silicon nitride passivation has been determined by x‐ray diffraction. The experimental stress tensor calculated from these strain values is in excellent agreement with the results of a finite element model calculation. Theintrinsicstress in the dielectric plays no role in influencing the stress in the metal; only thermal stress effects are important.

ISSN:0003-6951    

DOI:10.1063/1.105075

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Bilayers of yttrium and amorphous silicon have been irradiated with 60 keV inert ions. Between liquid‐nitrogen temperature and 100 °C, ion mixing resulted in an amorphous alloy of Y and Si. For temperatures of 125–190 °C, we observed formation of the YSi phase. YSi is not formed during thermal anneals of bilayers. Ion mixing at higher temperatures (≥205 °C) results in the formation of the stable YSi1.7phase. Such sequential silicide formation has not been observed for comparable rare‐earth silicides. The minimum temperatures for ion‐induced YSi1.7formation agrees with the prediction by a simple model which correlates vacancy mobility to phase transformation. The YSi formation temperature is associated with the onset of radiation‐enhanced diffusion. This temperature does not correlate well with the prediction of the model, but agrees with a scaling based on the average cohesive energy.

ISSN:0003-6951    

DOI:10.1063/1.105076

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The presence of a thin amorphous intermixed layer at the platinum‐GaAs interface in as‐deposited Pt/GaAs and Si/Pt/GaAs samples has been investigated via high‐resolution electron microscopy, microdiffraction, and energy dispersive spectroscopy. The intermixed layer forms below the native oxide of the GaAs substrate and consists of three elements, platinum, gallium, and arsenic. We suggest that this layer forms during the deposition process of the platinum.

ISSN:0003-6951    

DOI:10.1063/1.105077

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report on the simultaneous, molecular beam epitaxy growth of GaAs on GaAs(001) and GaAs(111)Bsubstrates at low temperatures. The crystallinity of the low‐temperature GaAs layers was assessed using a double‐crystal x‐ray diffractometer and a wide‐angle diffractometer with a rotating specimen stage. Layers were grown at 200 and 250 °C to a thickness of 3 &mgr;m on both (001) and (111) orientated substrates and an additional 3 &mgr;m layer was grown on GaAs(111)Bat 300 °C. Double‐crystal diffractometry confirmed the presence of a single crystalline layer, with a growth‐temperature‐dependent excess As concentration, on the (001) substrates. On the (111) substrates, only a polycrystalline layer was observed. A possible explanation for these observations based on growth surface roughening is presented.

ISSN:0003-6951    

DOI:10.1063/1.105078

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We have measured the electron energy‐loss spectrum (EELS) of BC3at sub‐eV resolution. Important differences between the total density of states of BC3at the threshold of theKedge, predicted by earlierabinitiocalculations, have been observed. We conclude from our measurements that the atomic arrangement in these materials can be described as graphite sheets with B replacing every third C atom. We suggest that further understanding of the electronic structure of BC3can be derived by comparing such EELS data with calculations of the local density of states of bulk BC3and including interlayer interaction.

ISSN:0003-6951    

DOI:10.1063/1.105053

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The carbon‐hydrogen complex in GaP is evidenced by the observation of the12C‐H,13C‐H, and12C‐D stretching local modes of vibration. Experiments performed with D2O enriched wet boric oxide encapsulant clearly shows that a source of hydrogen contamination during liquid‐encapsulation Czochralski growth is the water contained in the encapsulant.

ISSN:0003-6951    

DOI:10.1063/1.105054

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Photoluminescence (PL) measurements are presented for thin epitaxial layers of InAs, 2.5 A˚<d<36 A˚, grown on InP(100) by molecular beam epitaxy. The combination of efficient carrier capture and PL redshift with increasing InAs thickness clearly indicate the formation of InAs quantum wells on the InP surface. Data are also presented for InAs/InP structures capped with strained layers of either GaAs or In0.5Al0.5As. Since radiative recombination within the InAs layers can be distinguished from PL arising from both bulk and surface defects, this system allows us to monitor the quality of both the InAs/InP and InAs/air interfaces via their influence on the InAs quantum well luminescence.

ISSN:0003-6951    

DOI:10.1063/1.105055

出版商:AIP    

年代:1991

数据来源: AIP