摘要:

Plastic deformation in passivated Al-1 wt &percent;Cu thin films was studiedin situusing a straining device in the transmission electron microscope. Both edge and screw dislocations were found to have caused slip on inclined {111} planes. Multiple slip was frequently observed as two or more sets of intersecting slip traces. Microstructural investigations of both unpassivated and passivated Al-1 wt &percent;Cu films indicate that grain size and encapsulation by passivating layers are major contributors to strength of a thin film with a particular thickness. Additional strengthening is also provided by interactions between dislocations on multiple slip systems. The roles of grain orientation and precipitates in plastic deformation are also discussed. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365584

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Diffusion of platinum at low temperatures is a convenient way to characterize vacancy profiles in silicon. This article summarizes the experiments performed to find a standard procedure, discusses the pitfalls and limitations, and shows the applicability of the method. The results of experiments with float-zone and Czochralski-grown samples in the temperature range from 680 to 842 °C were found to disagree with the predictions of models published in the literature. Therefore, parameters governing the diffusion of point defects and platinum in silicon were determined for this temperature range. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365796

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The reactivation kinetics of passivated boron acceptors in hydrogenated silicon during zero bias annealing in the temperature range of 65–130 °C are reported. For large annealing times and high annealing temperatures, the reactivation process follows second-order kinetics and is rate limited by a thermally activatedH˜2complex formation process. For short annealing times and low annealing temperatures, the reactivation rate is found to be larger than that due toH˜2complex formation alone. We conclude that the faster reactivation is caused by the diffusion of the liberated hydrogen atoms into the bulk as well asH˜2complex formation. The effective diffusion coefficient of hydrogen is measured and found to obey the Arrhenius relation with an activation energy (1.41±0.1) eV. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365797

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

This work reports a statistical analysis of the evolution of polygranular segment lengths during high-temperature annealing of Al(Cu) thin-film interconnects with quasi-bamboo microstructures. To create samples of Al(Cu) lines that could be imaged by transmission electron microscopy without breaking or thinning, the lines were deposited on electron-transparent silicon nitride films (the “silicon nitride window” technique). The microstructures of the lines were studied as a function of annealing time and temperature. In particular, the distribution of polygranular segment lengths was measured. The results show that the longer polyglranular segments are preferentially eliminated during post-pattern annealing. As a consequence, the segment-length distribution narrows monotonically during annealing, and changes in shape. The preferential loss of the longest polygranular segments leads to a dramatic increase in resistance to electromigration failure.

ISSN:0021-8979    

DOI:10.1063/1.365760

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Polycrystalline bcc W layers, 110 nm thick with 011 preferred orientation and an average grain size of 40 nm, were grown on amorphous-SiO2/Si(001)substrates by ultrahigh vacuum (UHV) magnetron sputter deposition atTs=600 °C.Al overlayers, 170 nm thick with strong 111 preferred orientation and an average grain size of 120 nm, were then deposited atTs=100 °Cwithout breaking vacuum. Changes in bilayer sheet resistanceRswere monitored continuously as a function of timetaand temperatureTaduring UHV annealing. In addition, area-averaged and local interfacial reaction paths, as well as microstructural changes as a function of annealing conditions, were determined by x-ray diffraction, Rutherford backscattering spectroscopy, transmission electron microscopy (TEM), and scanning TEM in which compositional distributions in cross-sectional specimens were obtained by energy-dispersive x-ray analysis using a 1 nm diam probe beam. The two tungsten aluminides which form,WAl4andWAl12,are nucleated essentially immediately with no measurable induction time.WAl4grains, extensively twinned, increase in size during the initial reaction, then stop growing as competitive growth in the diffusion limited regime favorsWAl12.Information from microstructural and microchemical analyses was used to model theRs(Ta,ta)data in order to determine reaction kinetics and activation energies. The results show thatWAl12growth is limited by W diffusion, with an activation energy of 2.7 eV, to the Al/aluminide interface. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365798

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Defects in Si-dopedInxAl1−xAs(0<x<0.4)epilayers on GaAs substrates were systematically investigated by deep-level transient spectroscopy. Three electron traps, ranging from 0.22 to 0.89 eV, were observed inInxAl1−xAsgrown by molecular beam epitaxy. Their energy levels can be extrapolated from those in theInxAl1−xAs/InPsystem. A low-temperature-grown buffer layer as well as thermal annealing were found to be capable of reducing the defects in the active layer effectively. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365799

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The bond-length relaxation inInP1−xAsxmonolayers epitaxially grown by metalorganic vapor-phase epitaxy on an InP(001) substrate has been investigated using the extended x-ray absorption fine structures on the AsKedge. The In–As bond lengths inInP1−xAsxmonolayers were determined over a wide range of As compositionx(0.08<x<0.80).We find that the In–As bond lengthRIn–AsinInP1−xAsxmonolayer shows an anomaly atx∼0.5;RIn–Asis compressed atx∼0.5, deviating from the linear interpolation between the values in a dilute limit(x<<1,As:InP) and the strained InAs monolayer(x=1).The As composition dependence ofRIn–Ascoincides with that observed for As atoms incorporated by a surface As–P exchange reaction. The mechanism of anomalous bond-length variation, associated with the change of local structure from the dilute limit to the strained monolayer, is discussed in terms of the elastic energy confined in a strained heterointerface. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365800

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Mg-doped GaN samples prepared by reactive molecular beam epitaxy have been investigated in an attempt to gain insight into the impurity incorporation and the origin of auto doping in otherwise undoped GaN films. The Hall and secondary ion mass spectroscopy data were utilized for the analysis of possible background impurities such as Si, O, and H in an effort to ascertain whether the background electron concentration is of impurity origin or native defect origin. The data appear to support the N vacancy as a possible cause of auto-n-type doping seen in undoped GaN. The effect of the ammonia flow rate on the incorporation of Mg atoms in GaN films and on the behavior of H were studied for layers grown onc-plane sapphire as well as 6H–SiC. Increased incorporation of Mg with larger ammonia flow rates is attributed to Ga vacancies and accompanying site selection. Moreover,p-GaNfilms grown under high ammonia flux are reported with a hole concentration, mobility, and resistivity of about8×1017 cm−3,26 cm2/V s,and 0.3 &OHgr; cm, respectively. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365801

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have investigated structural properties of GaAs grown on top of a pseudomorphic Si interlayer deposited on a GaAs substrate by x-ray reflectivity and Bragg scattering. The surface and interface roughness of the 500-Å thick GaAs overlayer depends critically on the thickness of the Si interlayer. The surface roughness increases from roughly 10 to 40 Å when the Si thicknesses increases from 3 to 5 Å, whereas the interface roughness remains roughly constant for Si thicknesses larger than 9 Å. The Laue oscillation of the GaAs(004) Bragg reflection together with the asymmetry of the intensity allow a precise determination of the pseudomorphic Si interlayer. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365802

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We show that the formation of self-organized pseudosuperlattices during homogeneous epitaxial growth ofSi1−yCyon Si(001) is a fundamental phenomenon not limited to special growth techniques. For samples grown at higher temperatures, and therefore, with higher concentration of nonsubstitutional carbon, we find contrast variations in cross-sectional transmission electron microscopy, roughly periodic in the growth direction in epitaxialSi1−yCyalloy layers. The periodicity is a monotonic function of growth temperature and growth rate. Although the final explanation of this phenomenon remains an open question, we are able to rule out several possible effects. These structures do not reflect a modulation in the substitutional C content, the formation of the C-richSinCphases, or the segregation of nonsubstitutional C-containing defect complexes up to a certain saturation level. Rather, we show that the layers formed during the different growth processes contain different amounts of carbon. There is no critical size of the C-containing defect complexes independent of growth conditions that could lead to the formation of the observed structures. The variation of the periodicity with growth rate and temperature is similar to surface diffusion processes with an activation energy of 0.94±0.04 eV, close to the value for Si adatom diffusion on a Si(001) surface. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365862

出版商:AIP    

年代:1997

数据来源: AIP