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for epitaxy results from its influence on the stage of film growth at which the coalescence of nuclei begins.
J W Matthews, School of Engineering and Applied Science, University of Virginia, Charlottesville High-temperature vaporisation phenomena Several techniques have resulted in recent advances in the study of vaporisation phenomena at high temperatures. The application of these techniques, particularly as they relate to equilibrium vaporisation processes, has resulted in increased knowledge of vaporisation reactions, vapour species and the thermodynamics of g a s solid and gas - gas equilibria. Vaporisation kinetics is presently in a somewhat less satisfactory condition, and consequently offers many opportunities for future exploration. Some techniques previously applied to thermodynamic studies appear to be suitable also for use in the elucidation of vaporisation kinetics.
R T Grimley, Department of Chemistry, Purdue University, Lafayette, Indiana Business meeting of the Thin Film Division Afternoon session
surface in a two-dimensional structure that is simply related to the dimensions and orientation of the substrate surface. Additional atoms may then result in formation of three-dimensional structures having the lattice constant of the deposited material. The crystalline orientation of these films can be dependant on the temperature, orientation and cleanness of the substrate. In some instances, the shape of the nuclei can also be determined. The application of lowenergy electron diffraction to some of the above points was discussed and illustrated with specific vapour - substrate systems.
,4 U MacRae, Bell Telephone Laboratories, Incorporated, Murray Hill, New Jersey Nucleation and growth obtained by different techniques--a comparison: Panel Discussion After introductory remarks by members of the Panel the following topics were discussed: How is nucleation affected by the "additional parameters"? ie those not present in evaporation, in the various methods? How is surface mobility in the different methods affected by those "additional parameters"? Are there any differences between the initial stages of film formation in the different methods?
Panel members: D W Pashley (evaporation) ; M H Francombe (sputtering); K R Lawless (electro-deposition); A Miller (vapour deposition) ; J P Hirth (theory). Moderator: K H Behrndt
Ferromagnetic properties of nearly perfect thin nickel platelets Nearly perfect single-crystal thin platelets of nickel and nickel alloy are readily grown non-epitaxially by reducing the halide. Thicknesses range from about 500 to over 105/~; areas extend to over 1 mm 2. Etching in HC1 reveals dislocation densities generally either of zero or of 103 to 104 cm -2. Ferromagnetic domain studies with the platelets have yielded the following results: (1) 180 ° walls with mixed N6el-Bloch character may co-exist with Bloch walls in both nickel and Ni-Co platelets at least 7000 A_ thick. The presence of a geometrically required crosstie spot establishes the partially N6elwall character; (2) One may precisely determine the applied field required to drive out a nucleus of reverse magnetization from the corner of a platelet by noting the form of the returning domain structure; (3) The 180 ° wall in a rectangular Ni-Co platelet with a simple closure pattern forms the arc of a circle in an applied field, ie, there is a uniform effective pressure acting along its length; (4) Topological restraints are largely responsible for hysteresis in nickel platelets several thousand angstroms thick. In small driving fields Ni-Co rectangualr platelets may have virtually no hysteresis or coercive force (He <0.01 Oe). In large fields there is hysteresis from irreversible topological changes, but there may still be no coercive force; and (5) Near the transitional thickness for crosstie walls the platelets show both coercive forces of several tenths of an oersted and an after-effect. The ferromagnetic resonance experiments of RodbeU with nickel platelets were also briefly metnioned.
R W De Blois, General Electric Research and Development Center, Schenectady, New York Scanning electron-diffraction observations daring film growth Metallic films have been deposited on to carbon-film substrates at room temperature inside a direct-recording transmission electrondiffraction system at a pressure of ~ 10 -8 torr. Intensity profiles across the Debye-Scherrer rings were obtained at 10- to 20-second intervals, corresponding typically to 10/~ increments in film thickness; thus diffraction patterns corresponding to the earliest stages of growth could be recorded. The films examined (eg, A1, Au, Ag, 80/20 Ni/Fe alloy) show an initially diffuse pattern at a mean thickness of the order of 10 A,. The pattern developes continuously into a Debye-Scherrer ring pattern and increases in intensity to a maximum; thereafter intensity decreases with film thickness. The directrecording technique permits precise measurement of the ring halfwidths and of relative ring intensity for evaluating any preferred orientation during growth. Representative specimens were also examined by transmission electron microscopy.
C W B Grigson and D B Dove, Bell Telephone Laboratories, Incorporated, Murray Hill, New Jersey Low-energy electron diffraction Low-energy electron diffraction is an ideal tool to use for investigating the arrangement of atoms at surfaces. Results obtained by using this technique on various classes of materials, including insulators, semiconductors and metals, indicate that initially deposited atoms from a gas or an evaporation are usually bound to the 604
It is expected that the papers presented will be published in the
Journal of Vacuum Science and Technology. It was announced during the business meeting that the membership of the Division now totals about 550, which is 25 per cent of the AVS membership. An Amendment to the By-Laws now makes the establishment of local Chapters of the Division possible. Thin-film workers in the New York area have already applied for Chapter status, Southern California is expected to follow shortly and similar efforts are under way in other parts of the country. The officers of the Division elected for 1965/66 were Chairman, Dr C A Neugebauer (General Electric Company, Schenectady, New York); Vice-Chairman, Professor J A Dillon (Brown University, Providence, Rhode Island); Secretary-Treasurer, Dr S P Wolsky (P R Mallory & Company, Burlington, Massachusetts); Past Chairman, Dr K H Behrndt (Bell Telephone Laboratories, Murray Hill, New Jersey). Elected to the Executive Committee for a term of two years were Dr M H Francombe, Dr L Maissel and D r A Miller. Professor E C Crittenden, Professor R W Hoffman and Dr R E Thun will serve on the Committee for another year. D r Klaus Behrndt said after the Symposium that it appeared t o him as a full success. All the presentations had been excellent and the material well organized. Professor Hirth had made the theoretical aspects clearer than he, Dr Behrndt, had ever heard or read them, Dr Pashley had given a very good review of the nucleation and growth phenomena resulting from different cleavage conditions and D r Matthews had treated the special case of face-centred cubic metals on sodium chloride where nucleation and growth depended on the number of nucleation centres resulting from different cleavage conditions. The most interesting papers of the afternoon had been those presented by Drs Grigson and MacRae. The former had shown that films of face-centred cubic materials were polycrystalline at very small film thicknesses whereas body-centred cubic iron displays amorphous diffraction patterns up to between 50 and 80 A_ and then recrystallizes rapidly upon increasing the film thickness. One of the important conclusions of Dr MacRae's work had been that gases absorbed initially on clean surfaces in arrangements that were equivalent and sometimes identical to those of evaporated solid materials. Thus these two methods had yielded results on film structure and nucleation in the very early stages of deposition.
Conferences and symposia European Vacuum Technology Seminar Varian Associates held their first European Vacuum Technology Seminar in Turin, Italy, on 12 to 15 October 1965. The meeting brought together scientists, engineers and students interested in the rapidly expanding field of ultra-high vacuum. Personnel from Varian SpA in Turin and from Palo Alto lectured on the theory and application of vacuum techniques. Demonstrations were staged of a wide range of vacuum devices. The sessions, patterned after workshops conducted by Varian's Vacuum Pro-
for epitaxy results from its influence on the stage of film growth at which the coalescence of nuclei begins.
J W Matthews, School of Engineering and Applied Science, University of Virginia, Charlottesville High-temperature vaporisation phenomena Several techniques have resulted in recent advances in the study of vaporisation phenomena at high temperatures. The application of these techniques, particularly as they relate to equilibrium vaporisation processes, has resulted in increased knowledge of vaporisation reactions, vapour species and the thermodynamics of g a s solid and gas - gas equilibria. Vaporisation kinetics is presently in a somewhat less satisfactory condition, and consequently offers many opportunities for future exploration. Some techniques previously applied to thermodynamic studies appear to be suitable also for use in the elucidation of vaporisation kinetics.
R T Grimley, Department of Chemistry, Purdue University, Lafayette, Indiana Business meeting of the Thin Film Division Afternoon session
surface in a two-dimensional structure that is simply related to the dimensions and orientation of the substrate surface. Additional atoms may then result in formation of three-dimensional structures having the lattice constant of the deposited material. The crystalline orientation of these films can be dependant on the temperature, orientation and cleanness of the substrate. In some instances, the shape of the nuclei can also be determined. The application of lowenergy electron diffraction to some of the above points was discussed and illustrated with specific vapour - substrate systems.
,4 U MacRae, Bell Telephone Laboratories, Incorporated, Murray Hill, New Jersey Nucleation and growth obtained by different techniques--a comparison: Panel Discussion After introductory remarks by members of the Panel the following topics were discussed: How is nucleation affected by the "additional parameters"? ie those not present in evaporation, in the various methods? How is surface mobility in the different methods affected by those "additional parameters"? Are there any differences between the initial stages of film formation in the different methods?
Panel members: D W Pashley (evaporation) ; M H Francombe (sputtering); K R Lawless (electro-deposition); A Miller (vapour deposition) ; J P Hirth (theory). Moderator: K H Behrndt
Ferromagnetic properties of nearly perfect thin nickel platelets Nearly perfect single-crystal thin platelets of nickel and nickel alloy are readily grown non-epitaxially by reducing the halide. Thicknesses range from about 500 to over 105/~; areas extend to over 1 mm 2. Etching in HC1 reveals dislocation densities generally either of zero or of 103 to 104 cm -2. Ferromagnetic domain studies with the platelets have yielded the following results: (1) 180 ° walls with mixed N6el-Bloch character may co-exist with Bloch walls in both nickel and Ni-Co platelets at least 7000 A_ thick. The presence of a geometrically required crosstie spot establishes the partially N6elwall character; (2) One may precisely determine the applied field required to drive out a nucleus of reverse magnetization from the corner of a platelet by noting the form of the returning domain structure; (3) The 180 ° wall in a rectangular Ni-Co platelet with a simple closure pattern forms the arc of a circle in an applied field, ie, there is a uniform effective pressure acting along its length; (4) Topological restraints are largely responsible for hysteresis in nickel platelets several thousand angstroms thick. In small driving fields Ni-Co rectangualr platelets may have virtually no hysteresis or coercive force (He <0.01 Oe). In large fields there is hysteresis from irreversible topological changes, but there may still be no coercive force; and (5) Near the transitional thickness for crosstie walls the platelets show both coercive forces of several tenths of an oersted and an after-effect. The ferromagnetic resonance experiments of RodbeU with nickel platelets were also briefly metnioned.
R W De Blois, General Electric Research and Development Center, Schenectady, New York Scanning electron-diffraction observations daring film growth Metallic films have been deposited on to carbon-film substrates at room temperature inside a direct-recording transmission electrondiffraction system at a pressure of ~ 10 -8 torr. Intensity profiles across the Debye-Scherrer rings were obtained at 10- to 20-second intervals, corresponding typically to 10/~ increments in film thickness; thus diffraction patterns corresponding to the earliest stages of growth could be recorded. The films examined (eg, A1, Au, Ag, 80/20 Ni/Fe alloy) show an initially diffuse pattern at a mean thickness of the order of 10 A,. The pattern developes continuously into a Debye-Scherrer ring pattern and increases in intensity to a maximum; thereafter intensity decreases with film thickness. The directrecording technique permits precise measurement of the ring halfwidths and of relative ring intensity for evaluating any preferred orientation during growth. Representative specimens were also examined by transmission electron microscopy.
C W B Grigson and D B Dove, Bell Telephone Laboratories, Incorporated, Murray Hill, New Jersey Low-energy electron diffraction Low-energy electron diffraction is an ideal tool to use for investigating the arrangement of atoms at surfaces. Results obtained by using this technique on various classes of materials, including insulators, semiconductors and metals, indicate that initially deposited atoms from a gas or an evaporation are usually bound to the 604
It is expected that the papers presented will be published in the
Journal of Vacuum Science and Technology. It was announced during the business meeting that the membership of the Division now totals about 550, which is 25 per cent of the AVS membership. An Amendment to the By-Laws now makes the establishment of local Chapters of the Division possible. Thin-film workers in the New York area have already applied for Chapter status, Southern California is expected to follow shortly and similar efforts are under way in other parts of the country. The officers of the Division elected for 1965/66 were Chairman, Dr C A Neugebauer (General Electric Company, Schenectady, New York); Vice-Chairman, Professor J A Dillon (Brown University, Providence, Rhode Island); Secretary-Treasurer, Dr S P Wolsky (P R Mallory & Company, Burlington, Massachusetts); Past Chairman, Dr K H Behrndt (Bell Telephone Laboratories, Murray Hill, New Jersey). Elected to the Executive Committee for a term of two years were Dr M H Francombe, Dr L Maissel and D r A Miller. Professor E C Crittenden, Professor R W Hoffman and Dr R E Thun will serve on the Committee for another year. D r Klaus Behrndt said after the Symposium that it appeared t o him as a full success. All the presentations had been excellent and the material well organized. Professor Hirth had made the theoretical aspects clearer than he, Dr Behrndt, had ever heard or read them, Dr Pashley had given a very good review of the nucleation and growth phenomena resulting from different cleavage conditions and D r Matthews had treated the special case of face-centred cubic metals on sodium chloride where nucleation and growth depended on the number of nucleation centres resulting from different cleavage conditions. The most interesting papers of the afternoon had been those presented by Drs Grigson and MacRae. The former had shown that films of face-centred cubic materials were polycrystalline at very small film thicknesses whereas body-centred cubic iron displays amorphous diffraction patterns up to between 50 and 80 A_ and then recrystallizes rapidly upon increasing the film thickness. One of the important conclusions of Dr MacRae's work had been that gases absorbed initially on clean surfaces in arrangements that were equivalent and sometimes identical to those of evaporated solid materials. Thus these two methods had yielded results on film structure and nucleation in the very early stages of deposition.
Conferences and symposia European Vacuum Technology Seminar Varian Associates held their first European Vacuum Technology Seminar in Turin, Italy, on 12 to 15 October 1965. The meeting brought together scientists, engineers and students interested in the rapidly expanding field of ultra-high vacuum. Personnel from Varian SpA in Turin and from Palo Alto lectured on the theory and application of vacuum techniques. Demonstrations were staged of a wide range of vacuum devices. The sessions, patterned after workshops conducted by Varian's Vacuum Pro-