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883. Method of detecting leaks in hermetically sealed objects
Classified
abstracts
881 -890
a screw motion and the objects are successively brought into contact with a series of side tubes creating successively greater degrees of vacuum, until finally the objects pass into the main evacuated space. On withdrawing the objects the reverse procedure applies. P I Bakhur and Yu A Ekimov, USSR Patent, No 341,877, appkd 3 Dee 1968, puhlrl3 Drc 1972. 25. BAFFLES, EQUIPMENT
TRAPS
AND
REFRIGERATION
‘5 881. Hieh-vacuum tran for diffusion numns. (USSR) This high-vacuum trab for diffusion-pumps ‘follows the conventional form of such devices except that, in order to reduce the thermal inertia of the cold guide, the latter has its inner walls made of porous material and is filled with krypton under a pressure of 5 atm. This gas has a vaporization temperature considerably higher than that of nitrogen. When the lower end of the tube is cooled with liquid nitrogen the effect of the different thermal characteristics of krypton and “thermal superconductivity” to the nitrogen is such as to impart cold guide, and the whole system works more efficiently. I G Khisameev, USSR Patent, No 339,677, appld 22 Ott 1969, puhld 1 I Jlrnp 1972. 27. LEAK
DETECTORS
AND
LEAK
DETECTION
‘7 882. Method of testing vacuum systems for hermetic sealing. (USSR) A modification of the standard method of leak testing by blowing suitable gases around suspected leaks in vacuum systems is described. The novel feature lies in the fact that two different test gases are used alternately with a constant period of alternation, typically at infra-sonic frequency. The alternating signals picked up from the periodic ‘packets’ of different molecules makes the leak tester extremely sensitive. V A Sagaidachnyi, USSR Patent, No 365,609, appld 5 Aug 1970. publd I9 March 1973. _1_
Ll
883. Method of detecting leaks in hermetically sealed objects. (USSR) A modification to the ordinary method of leak detection based on indicator gases is described; in the new version sensitivity is enhanced by allowing the indicator gas passing through the leak to fall into a galvanic cell with a solid electrolyte possessing ionic conductivity. The emf of the cell is measured and the magnitude of the leak is deduced by determining any deviation of this emf from standard value. A S Guzei et al, USSR Patent, No 333,432, crppld 15 Sepf 1970, prrhld I5 Mav 1972.
III.
Vacuum
30. EVAPORATION
applications AND
SPUTTERING
30 884. Single source evaporation of a niobium based alloy containing volatile constituents. (USA) By adding excess niobium to the molten metal pool of a rod-fed evaporation source in order to approximate a steady state condition, reproducible transfer of source material containing niobium, titanium, chromium, and aluminium has been achieved. Single source evaporative coating of this material has not been considered practical prior to this work because of the factor of IO6 difference in vapor pressure between the most volatile element and the least volatile element. As produced, the coatings had a banded structure. A heat treatment homogenized the coatings. A model is suggested to explain the banded structure. W R Stowell, J Vat Sci Technol, 10, (4), July-Alcg 1973, 489-493. 30 885. The growth of Au on PbS, PbSe, PbTe, and SnTe thin film substrates. (USA) The formation of thin Au films by vacuum evaporation on lead and tin chalcogenides is investigated. Single crystal chalcogenide substrates are prepared by vacuum evaporation onto KCI. The films are studied by RHEED prior to removal from the KC1 substrate and by TEM and TED after removing the composite Au-chalcogenide film from the KC]. A remarkable variety of orientations and particle 466
shapes is observed. The saturation particle density varies over a very wide range as a function of substrate material and temperature. Results are discussed and compared with the growth of Au on alkali halides. A K Green et al, J Vat Sci Technol. 10 (4). Julym-Au~g 1973, 494-502. 30 886. Ion-plated copper-steel graded interface. (USA) Copper was ion plated onto a steel substrate to form a highly adherent surface coating. Electron probe examination of the copper/steel interfacial region showed that the ion-plated copper had penetrated the steel substrate to a depth of about 7-8 TVto form a graded, diffuse interface. The excellent adhesion of the coating to the substrate, which was examined by a 90 bend test and the standard Scotch Tape Test, can be attributed to the diffused interface formed by ion plating. B Swaroop and I Adler, J Vat Sci Technol, 10 (4), July--Auq 1973. 503-505. 30 887. Kinetics and thermodynamics of the deposition of zinc films on germanium (110) and (100) surfaces. (USA) The initial stages of the deposition of thin zinc films on the (I IO) and (100) surfaces of germanium single crystals have been studied. A mass-spectrometric molecular beam method was used in ultrahigh vacuum. The evaporation rate of the thin film was measured during depositions at various temperatures and beam intensities. On both substrates, the adcoverage approaches complete saturation of available adsorption sites before nucleation of bulk zinc starts Nucleation therefore occurs on a composite substrate. On (I IO) substrate, the critical nucleation stage of thin film formation is determined by the coverage only. The thermodynamic parameters of the critical deposits, such as the equilibrium evaporation rate, the thermodynamic potential, and the differential binding energy, have been determined. These thermodynamic parameters determine the critical beam intensity necessary for nucleation. The deposition of zinc on (100) substrates is more complex. The critical nucleation state of the deposit is determined not solely by the coverage, but also by the deposition conditions of temperature and beam intensity. In such a case, thermodynamic parameters cannot be obtained by the present technique. R J H Voorhoeve and J N Carides, J Vat Sci Technol, 10 (4), Ju/J’Al&_/ 1973, 513-519. 30 888. Cr-Cu and Cr-Cu-Cr thin film metallization. (USA) Thin film sandwiches of Cr-Cu and Cr-CupCr are widely used for a number of electronic applications, but there has been no report of any systematic investigation of interactions or stability in these films. A study of diffusion, oxidation, and stability in these films using resistometric techniques and electron diffraction and shows that these systems are useful only at low temperature (- I75 C) in oxidizing environments. At high temperatures in any environment, oxidation and diffusion result in many problems: resistivity instabilities, oxidation. hardening (bonding problems), variable solderability, and extreme difficulty in dielectric overcoating. Techniques are discussed to circumvent some of these problems. J J O’Neill and J L Vossen, J Vat Sci Technol, 10 (4). July-Aug 1973, 533-538. 30 889. Graphite substrate heater. (USSR) A new form of graphite substrate heater for use in the deposition of thin films is described. In contrast to existing models, the new heater is arranged so as to keep the surface of the substrate at a specified constant temperature. This is achieved by connecting the plate of the graphite heater to its electrodes through conductors, the cross sectional area of which is smaller than the cross sectional area of the plate. A convenient ratio of these areas is 35: I. The material of the conductors is selected in such a way as to pass the same current as would have been passed with the conventional direct-heating arrangement. The ends of the plates are coated with copper to improve contact. A A Komarov and Z M Lerman, USSR Patent, No 347.367, appld 3 I Drc 1969, puhll I Sept 1972. 30 890. Apparatus for the ionic deposition of films on cylindrical surfaces. (USSR) An apparatus facilitating the ionic deposition of films on cylindrical surfaces at a higher rate than existing devices is described. The improvement is achieved by having an evaporator made in the form
abstracts
881 -890
a screw motion and the objects are successively brought into contact with a series of side tubes creating successively greater degrees of vacuum, until finally the objects pass into the main evacuated space. On withdrawing the objects the reverse procedure applies. P I Bakhur and Yu A Ekimov, USSR Patent, No 341,877, appkd 3 Dee 1968, puhlrl3 Drc 1972. 25. BAFFLES, EQUIPMENT
TRAPS
AND
REFRIGERATION
‘5 881. Hieh-vacuum tran for diffusion numns. (USSR) This high-vacuum trab for diffusion-pumps ‘follows the conventional form of such devices except that, in order to reduce the thermal inertia of the cold guide, the latter has its inner walls made of porous material and is filled with krypton under a pressure of 5 atm. This gas has a vaporization temperature considerably higher than that of nitrogen. When the lower end of the tube is cooled with liquid nitrogen the effect of the different thermal characteristics of krypton and “thermal superconductivity” to the nitrogen is such as to impart cold guide, and the whole system works more efficiently. I G Khisameev, USSR Patent, No 339,677, appld 22 Ott 1969, puhld 1 I Jlrnp 1972. 27. LEAK
DETECTORS
AND
LEAK
DETECTION
‘7 882. Method of testing vacuum systems for hermetic sealing. (USSR) A modification of the standard method of leak testing by blowing suitable gases around suspected leaks in vacuum systems is described. The novel feature lies in the fact that two different test gases are used alternately with a constant period of alternation, typically at infra-sonic frequency. The alternating signals picked up from the periodic ‘packets’ of different molecules makes the leak tester extremely sensitive. V A Sagaidachnyi, USSR Patent, No 365,609, appld 5 Aug 1970. publd I9 March 1973. _1_
Ll
883. Method of detecting leaks in hermetically sealed objects. (USSR) A modification to the ordinary method of leak detection based on indicator gases is described; in the new version sensitivity is enhanced by allowing the indicator gas passing through the leak to fall into a galvanic cell with a solid electrolyte possessing ionic conductivity. The emf of the cell is measured and the magnitude of the leak is deduced by determining any deviation of this emf from standard value. A S Guzei et al, USSR Patent, No 333,432, crppld 15 Sepf 1970, prrhld I5 Mav 1972.
III.
Vacuum
30. EVAPORATION
applications AND
SPUTTERING
30 884. Single source evaporation of a niobium based alloy containing volatile constituents. (USA) By adding excess niobium to the molten metal pool of a rod-fed evaporation source in order to approximate a steady state condition, reproducible transfer of source material containing niobium, titanium, chromium, and aluminium has been achieved. Single source evaporative coating of this material has not been considered practical prior to this work because of the factor of IO6 difference in vapor pressure between the most volatile element and the least volatile element. As produced, the coatings had a banded structure. A heat treatment homogenized the coatings. A model is suggested to explain the banded structure. W R Stowell, J Vat Sci Technol, 10, (4), July-Alcg 1973, 489-493. 30 885. The growth of Au on PbS, PbSe, PbTe, and SnTe thin film substrates. (USA) The formation of thin Au films by vacuum evaporation on lead and tin chalcogenides is investigated. Single crystal chalcogenide substrates are prepared by vacuum evaporation onto KCI. The films are studied by RHEED prior to removal from the KC1 substrate and by TEM and TED after removing the composite Au-chalcogenide film from the KC]. A remarkable variety of orientations and particle 466
shapes is observed. The saturation particle density varies over a very wide range as a function of substrate material and temperature. Results are discussed and compared with the growth of Au on alkali halides. A K Green et al, J Vat Sci Technol. 10 (4). Julym-Au~g 1973, 494-502. 30 886. Ion-plated copper-steel graded interface. (USA) Copper was ion plated onto a steel substrate to form a highly adherent surface coating. Electron probe examination of the copper/steel interfacial region showed that the ion-plated copper had penetrated the steel substrate to a depth of about 7-8 TVto form a graded, diffuse interface. The excellent adhesion of the coating to the substrate, which was examined by a 90 bend test and the standard Scotch Tape Test, can be attributed to the diffused interface formed by ion plating. B Swaroop and I Adler, J Vat Sci Technol, 10 (4), July--Auq 1973. 503-505. 30 887. Kinetics and thermodynamics of the deposition of zinc films on germanium (110) and (100) surfaces. (USA) The initial stages of the deposition of thin zinc films on the (I IO) and (100) surfaces of germanium single crystals have been studied. A mass-spectrometric molecular beam method was used in ultrahigh vacuum. The evaporation rate of the thin film was measured during depositions at various temperatures and beam intensities. On both substrates, the adcoverage approaches complete saturation of available adsorption sites before nucleation of bulk zinc starts Nucleation therefore occurs on a composite substrate. On (I IO) substrate, the critical nucleation stage of thin film formation is determined by the coverage only. The thermodynamic parameters of the critical deposits, such as the equilibrium evaporation rate, the thermodynamic potential, and the differential binding energy, have been determined. These thermodynamic parameters determine the critical beam intensity necessary for nucleation. The deposition of zinc on (100) substrates is more complex. The critical nucleation state of the deposit is determined not solely by the coverage, but also by the deposition conditions of temperature and beam intensity. In such a case, thermodynamic parameters cannot be obtained by the present technique. R J H Voorhoeve and J N Carides, J Vat Sci Technol, 10 (4), Ju/J’Al&_/ 1973, 513-519. 30 888. Cr-Cu and Cr-Cu-Cr thin film metallization. (USA) Thin film sandwiches of Cr-Cu and Cr-CupCr are widely used for a number of electronic applications, but there has been no report of any systematic investigation of interactions or stability in these films. A study of diffusion, oxidation, and stability in these films using resistometric techniques and electron diffraction and shows that these systems are useful only at low temperature (- I75 C) in oxidizing environments. At high temperatures in any environment, oxidation and diffusion result in many problems: resistivity instabilities, oxidation. hardening (bonding problems), variable solderability, and extreme difficulty in dielectric overcoating. Techniques are discussed to circumvent some of these problems. J J O’Neill and J L Vossen, J Vat Sci Technol, 10 (4). July-Aug 1973, 533-538. 30 889. Graphite substrate heater. (USSR) A new form of graphite substrate heater for use in the deposition of thin films is described. In contrast to existing models, the new heater is arranged so as to keep the surface of the substrate at a specified constant temperature. This is achieved by connecting the plate of the graphite heater to its electrodes through conductors, the cross sectional area of which is smaller than the cross sectional area of the plate. A convenient ratio of these areas is 35: I. The material of the conductors is selected in such a way as to pass the same current as would have been passed with the conventional direct-heating arrangement. The ends of the plates are coated with copper to improve contact. A A Komarov and Z M Lerman, USSR Patent, No 347.367, appld 3 I Drc 1969, puhll I Sept 1972. 30 890. Apparatus for the ionic deposition of films on cylindrical surfaces. (USSR) An apparatus facilitating the ionic deposition of films on cylindrical surfaces at a higher rate than existing devices is described. The improvement is achieved by having an evaporator made in the form