摘要:

We have developed a new precise imaging technique for atomic force microscopy (AFM) and observed complicated surface structures of integrated circuit (IC) devices by this technique. This technique consists of a hopping mode operation and use of a zinc oxide whisker as a probing tip with high aspect ratio. In this operation, topographic data of the surface structures are obtained under a constant repulsive force at each measuring point, and after each measurement the probing tip is withdrawn from the surface and moved to the next measuring point. The contact holes with a diameter of ∼1 &mgr;m and a depth of 1.5 &mgr;m fabricated on IC devices have been successfully imaged in this AFM imaging technique.

ISSN:0021-8979    

DOI:10.1063/1.355313

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

Epitaxialn‐type GaAs samples were studied before and after irradiation with 7 MeV electrons at fluences varying from 1×1013to 5×1015/cm2. The measurements involved the Hall effect and resistivity from 15 to 300 K. Fitting of the data revealed the evolution of the density and activation energy of impurity levels as a function of fluence. At the higher fluences, the carrier concentration and mobility decrease as expected but at the lower fluences, both of these quantities increase in a manner that depends on doping and fluence levels, and on temperature. The results are consistent with the radiation‐stimulated gettering effect. It is shown that the maximum observed in the Hall coefficient as a function of temperature is possibly due to a manifestation ofDXcenters in the absence of applied pressure.

ISSN:0021-8979    

DOI:10.1063/1.354402

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

The amorphization of an Fe‐Zr multilayer film due to ion‐beam mixing with protons and due to solid‐state reaction is studied in detail using backscatter Mo¨ssbauer spectroscopy, x‐ray diffraction, and Auger electron spectroscopy. The local structure of the amorphous phase produced by both processes is found to be very similar based on the Mo¨ssbauer results. The dose dependence of the ion‐beam‐mixed phase fraction can be accounted for approximately by a collision cascade mixing model. Incomplete amorphization of the Fe was observed as a result of the proton irradiation with a large enough dose to produce apparent saturation whereas complete amorphization occurred for the identical multilayer structure via solid‐state reaction. The latter was characterized by a thermal activation energy of 0.7 eV.

ISSN:0021-8979    

DOI:10.1063/1.354403

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

Implantation of hydrogen at 600 °C into GaAs at 8 keV and at high doses resulted in the formation of a two‐layer structure. The topmost layer roughly extended in depth to the range of the protons and exhibited a high concentration of loops, hydrogen bubbles, decorated dislocations, and faults. Occasional microsplits on {110} were observed. The deeper layer contained pressurized hydrogen platelets on {111}. These results are critically compared with previous results obtained with cold implanted and subsequently annealed GaAs. The present observations are also discussed in relation to the theoretical treatment by d’Olieslaeger [J. Mater. Sci.23, 2697 (1988)]. Estimates of the importance of arsine production are also presented.

ISSN:0021-8979    

DOI:10.1063/1.354404

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

The production of electrically active defect centers in molecular beam epitaxy (MBE) GaAs irradiated with low energy (50–500 eV) Sn ions during growth has been investigated as a function of ion energy. GaAs was dopedntype during growth with a specially designed Sn focused ion beam column mounted on a MBE growth chamber. The 77 and 300 K Hall mobility and carrier concentration of the GaAs depended strongly on the ion energy, thus providing a sensitive measure of the concentration of ion‐induced acceptorlike defect centers. The material was found to be nonconducting for ion energies greater than 200 eV, while a systematic decrease in the acceptor concentration, and consequent increase in the mobility, was observed as the ion energy was decreased below this value. A peak mobility of 90 000 cm2 V−1 s−1at a carrier concentration of 1×1014cm−3was achieved (at 60 K) which is in excess of that obtained in other reports of ion‐doped GaAs. A similar dependence on ion energy was found in the 4.2 K photoluminescence spectra of the ion‐doped GaAs, characterized by the appearance of a broad acceptor level peak and a decrease in the overall luminescent intensity with increasing ion energy. The lowest energy doped samples provided high quality spectra with narrow linewidths comparable with thermal (Si) doped material. Using the above data, a mechanism is proposed for the production of acceptor centers in this system.

ISSN:0021-8979    

DOI:10.1063/1.354405

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

A closed‐form solution for diffusion in two dimensions is obtained for impression creep of a thin film by a straight punch. The results show that for a rigid impermeable substrate the penetration rate is proportional directly to the thickness of the film and inversely to the square of the punch width. Without the substrate the penetration rate is inversely proportional to the thickness of the film and independent of the punch width.  

ISSN:0021-8979    

DOI:10.1063/1.354406

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

The diffusion problem in the impression creep of a thin film by a cylindrical punch is analyzed. It is found that at low stresses the impression velocity is proportional to the punching stress. For the same punching stress and the same punch radius the impression velocity decreases for a rigid substrate, and increases without the substrate as the thickness of film decreases. Two limiting cases for the rigid substrate agree with the previous work, namely, the impression velocity is inversely proportional to the punch radius for impression creep of a half‐space, and inversely proportional to the square of the punch radius for impression creep of a thin film. Without the substrate the impression velocity for impression creep of a thin film is inversely proportional to the thickness of the film and independent of the punch radius.  

ISSN:0021-8979    

DOI:10.1063/1.354407

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

X‐ray diffraction and electron probe microanalysis were used to determine the phase equilibria in the In‐Pt‐P system at 725 and 600 °C. The observed binary phases were consistent with the assessed phase diagrams from the literature. Three ternary phases were found. The major difference between the 725 and 600 °C isotherms was the phases in equilibrium with InP. At 600 °C, the binary phases Pt3In7and PtP2were in equilibrium with InP. However, a tie‐line transition from InP‐Pt3In7to In‐PtP2was found between 600 and 725 °C. The binary phases which were found to be stable in thin film form on InP were consistent with the phase equilibria data. From the tie‐line change, the enthalpy of formation of PtP2at 298 K was estimated to be −350±40 kJ/mol.

ISSN:0021-8979    

DOI:10.1063/1.354410

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

Interfacial reactions in Pt/InP contacts were examined by transmission electron microscopy and Auger depth profiling. A solid state amorphization reaction occurred after the contacts were annealed for 60 s at 325 °C. Crystallites were observed in the amorphous layer near the boundary between the amorphous phase and the remaining Pt upon annealing at 350 °C. The predominant phase formed upon crystallization was polycrystalline Pt5InP. A cubic phase, which is most likely a supersaturated solution of phosphorus in Pt3In, also formed. As the annealing temperature was increased, the reaction proceeded with the formation of phases that were richer in In and P. For 60 s anneals at temperatures of 500 °C or greater, Pt‐In phases and textured PtP2were observed, and the film/InP interface exhibited roughness on the scale of tens of nanometers. Both the Pt‐In phases and PtP2were present at the film/InP interface.

ISSN:0021-8979    

DOI:10.1063/1.354411

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

An experiment of diffusing Zn into GaAs has been conducted at 900 °C using Zn metal as the source material in a quartz ampoule, with or without As being included. For cases without further including As in the ampoule, the Zn profile is box shaped and the Zn‐diffused region contains dislocations and void/Ga‐precipitate pairs, with the void to precipitate volume ratio being essentially constant throughout the Zn‐diffused region. For cases including As in the ampoule, the Zn profile is of the kink‐and‐tail type with the Zn‐diffused region containing dislocations and void/Ga‐precipitate pairs. In the profile tail region, the Ga‐precipitate to void volume ratio is substantial, while in the profile kink region of high Zn concentration near the surface only voids are left. The results are interpreted in accordance with Zn and diffusion‐ambient‐induced Ga‐As‐Zn ternary alloy system thermal equilibrium requirements in general, and the consequential solid phase composition variations in particular. Without As inclusion in the ampoule, the overall Ga‐As material Ga concentration in the Zn‐diffused region has exceeded the allowed limit of the GaAs crystal, with the crystal composition at a limit. With the inclusion of As in the ampoule, the GaAs crystal composition in the high Zn concentration region near the surface has reached an allowed As concentration limit, but in the profile tail region the overall Ga‐As material Ga concentration has exceeded an allowed limit of the GaAs crystal. This is because the vapor phase Zn and As species constitute two conflicting thermodynamic driving forces for producing GaAs crystals with two opposite and extreme compositions: As for producing As‐rich crystals, and Zn for producing Ga‐rich materials. The common assumption that the inclusion of As in the diffusion ampoule will ensure the whole GaAs crystal essentially at an As‐rich composition does not hold during high‐concentration Zn indiffusion.

ISSN:0021-8979    

DOI:10.1063/1.354412

出版商:AIP    

年代:1993

数据来源: AIP