摘要:

We present a detailed study ofn+\p\p+silicon diodes irradiated with fluences of 1 MeV electrons high enough to cause device failure due to majority carrier removal. Capacitance–voltage(C–V)measurements were used to monitor the change in the carrier concentration of the base of the device as a function of radiation fluence. These were compared to the defect spectra in the same region obtained by deep level transient spectroscopy, and to the current–voltage characteristics of the device, both before and after annealing. We observed the expected deep levels with activation energies of 0.18 and 0.36 eV, but theC–Vresults imply that other trap levels must play a more important role in the carrier removal process. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365631

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Correlation betweenp-type andn-type Si recombination lifetimes enables us to roughly but rapidly predict the isolation of iron, copper, and stainless-steel components. We examine this correlation method in detail and show that the ratio ofp-type Si andn-type Si lifetimes is not 1:1 but 0.67:1 for iron and 1:0.67 for copper. Some kind of precipitates may be responsible for these ratios. The advantages of the correlation method are quantitatively demonstrated for wafer cleaning, furnace processes, and plasma etching processes. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365632

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

By using a thin13Cdiamond chip together with a12Cdiamond chip as sensors, the diamond Raman spectra provide the means to measure pressure precisely (±0.3 GPa) at any temperature (10–1200 K) and simultaneous hydrostatic (or quasihydrostatic) pressure (0–25 GPa) foranysample compatible with an externally heated diamond-anvil cell. Minimum interference between the Raman spectrum from the diamond anvils and those of the pressure sensors is obtained by measuring pressures with the Raman signal from the13Cdiamond chip up to 13 GPa, and that from the12Cchip above 10 GPa. The best crystallographic orientation of the diamond anvils is with the [100] direction along the direction of applied force, in order to further minimize the interference. At 298 K, the pressure dependence of the13Cdiamond first-order Raman line is given by&ngr;(P)=&ngr;RT+aPfor 91 at. &percent;13Cdiamond, where&ngr;RT(13C)=1287.79±0.28 cm−1anda(13C)=2.83±0.05 cm−1/GPa.Analysis of values from the literature shows that the pressure dependence of the Raman line of12Cdiamond is best described by the parameters&ngr;RT(12C)=1332.5 cm−1anda(12C)=2.90±0.05 cm−1/GPa.The temperature dependence of the diamond Raman line is best described by&ngr;(T)−&ngr;RT=b0forT⩽200 K,and&ngr;(T)−&ngr;RT=b0+b1.5Tk1.5for200 K⩽T⩽1500 K,whereTk=T−200 K.For 91 at. &percent;13Cdiamond, the parameters areb0=0.450±0.025 cm−1;b1.5=−(7.36±0.09)×10−4 cm−1 K−1.5;and for12Cdiamond, the parameters areb0=0.467±0.033 cm−1,b1.5=−(7.56±0.10)×10−4 cm−1 K−1.5.Although no quantitative theoretical models are available for calculating the Raman shift as a function of temperature, the excellent fits to the data suggest that theTk1.5dependence above has a physical basis. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.366268

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The true hardness of thin film is assessed through micromechanical analysis of the composite hardness measured by a microindentation tester. In partitioning the respective contributions of the film and the substrate to the composite hardness, we apply the modified plastic-zone volume-law-of-mixtures theory by analyzing the indentation stress field of a film/substrate system. At this time, while the substrate is assumed to undergo radial deformation, the film is assumed to be deformed mainly parallel to the surface. On the basis of these stress analyses, the influence of interface is incorporated; the deformation in the softer material is constrained by interface bonding and the plastic-zone radii are modified by considering the respective virtual pressures that the film and the substrate actually support. When an interface has perfect bonding, the hardness value for a film can be calculated analytically from the condition of strain matching at the interface—approximately2200 kgf/mm2for diamondlike carbon (DLC) films deposited on WC–Co substrates. On the other hand, when the interface is weak, an interface parameter &kgr; is introduced to describe the partial release of film constraint due to interface delamination. For DLC films on Si substrates, the expansion rate of the extent of this partial release is constant regardless of both the film thickness and indentation load, so that it can be used as a measure of adhesion loss. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365633

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We present a new type of experiment on the nonlinear interaction between coherent collinear longitudinal acoustic waves: Two waves with different frequencies propagate together successively in a liquid and in a solid. They interact because of the nonlinear elastic properties of both media. We have measured the magnitude of the signal resulting from the interaction, as a function of the liquid thickness. The variation law is sensitive to the phase difference between the waves generated in both media (in phase or out of phase). From this dependence the ratio and relative sign of two parameters characterizing the non-linear properties of both media can be derived without any measurement of the primary and harmonic waves amplitude. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365634

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The kinetics of theCu3Gephase formation during reactions between 600 nm polycrystalline Cu (poly-Cu) and 600 nm amorphous Ge (a-Ge) layers on Si (100) substrates have been studied as a function of annealing conditions. MonoclinicCu3Genucleated rapidly, resulting in smoothCu3Gelayers. The room-temperature resistivity of theCu3Gewas ∼8 &mgr;&OHgr; cm (∼4.5 times that of pure Cu). The real-time resistance versus temperature[R(T)]characteristics were nearly identical for heating rates of 0.1–5 °C/min. Modeling of theR(T)data indicates that the reaction was predominantly diffusion controlled with a rate of(4×10−3 cm2/s)exp [−0.85±0.01eV/kT] wherek=8.617×10−5 eV/K.Secondary ion mass spectrometry profiles andR(T)data for the films annealed to various temperatures indicate that theCu3Ge/Geinterface is stable forT<300 °C.©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365635

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Low-temperature(∼200 °C)molecular beam epitaxy ofGe1−xCxalloys grown on Si(100) have been extensively investigated byin situreflection high-energy electron diffraction,ex situx-ray diffraction, transmission electron microscopy, and Raman spectroscopy. Carbon concentrations were nominally varied from 0 up to ∼10 at. &percent;. Selected samples were annealed in an Ar ambient at 750 °C to evaluate the stability of the thin films. A few films were also grown on Ge substrates. With increasing C concentration, the epitaxial growth mode changes from two dimensional layer growth to three dimensional island growth. The surface has a tendency to facet along {311} planes under certain growth conditions. The microstructure shows an increase in planar defect density with increasing C concentration. The x-ray diffraction data show that the lattice parameter decreases with increasing C concentration and that a maximum of 1 at. &percent; C is incorporated substitutionally in Ge. Raman spectroscopy shows no clear Ge–C signal though extra intensity is measured at the energies where Ge–C modes may be expected. Films with nominal C concentrations greater than 2 to 3 at. &percent; show clear evidence for amorphous C. We propose that under our growth conditions, nominal C in excess of about 2 to 3 at. &percent; remains on the surface as amorphous C and plays an important role in 3D islanding, defect formation, and {311} faceting during epitaxial growth. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365636

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We demonstrate the asymmetric lattice distortion of pseudomorphic superlattices grown on misoriented substrates. High-resolution x-ray diffractometry has been employed to study InGaAs/GaAs superlattices grown by molecular beam epitaxy on (111)B GaAs with a miscut angle of 1°. We observe the nontrigonal deformation of the InGaAs unit cells, while the GaAs cells retain the cubic symmetry. This result is in accord with the behavior predicted by the anisotropic elasticity theory. Consequently, the threefold symmetry of the [1¯1¯1¯] axis is lost and, therefore, the interpretation of the diffraction profiles must take account of the actual Miller indices of the substrate surface and reflecting planes used during each measurement. Otherwise, a non-negligible error in the determination of the period thickness and indium fraction could be introduced. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365637

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

ZnCdMgSe epitaxial layers grown on InP (001) substrates have been characterized by etch pit density (EPD) measurements. A hydrobromic acid and acetic acid solution at a concentration of 1:7 by volume was found to work well for the EPD measurements. Atomic force microscopy (AFM) was used to characterize the morphology of the etched surface. The AFM results showed that the etch pit depth became constant after a depth corresponding to roughly the II-VI layer thickness. The accuracy of the etch pit density method for revealing stacking faults and dislocations was verified by plan-view transmission electron microscopy (TEM). Both stacking faults and threading dislocations originating from misfit dislocations were revealed by this etchant. The TEM and AFM results showed that the etching is very selective. We show that we have grown ZnCdMgSe layers with an EPD of∼106 cm−2.©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365638

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Substrate materials used for growing diamond films were observed to modify thin films’ electron field emission properties significantly. Using heavily doped silicon (LR-Si) as a substrate lowered the turn-on field from(E0)Si=14.4 V/&mgr;mto(E0)LR-Si=9.7 V/&mgr;mand increased the emission current density from(Je)Si=4 &mgr;A/cm2to(Je)LR-Si=40 &mgr;A/cm2(at 16 V/&mgr;m). However, electron field emission properties can be further improved only by using Au precoatings to modify the characteristics of interfacial layer. The turn-on field was lowered further to(E0)Au–Si=8.7 V/&mgr;mand emission current density was increased further to(Je)Au–Si=400 &mgr;A/cm2(at 16 V/&mgr;m). Secondary ion mass spectroscopic examination indicated that the main interaction is the outward diffusion of Au species into amorphous carbon layer, lowering the resistivity of this interfacial layer. The electrons can therefore be transported easily from Si substrate across the interfacial layer to the diamonds and subsequently field emitted. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365639

出版商:AIP    

年代:1997

数据来源: AIP