The layering transition of a physisorption system on a metal single crystal has been investigated by means of an ellipsometry and an eXtremely-low-current LEED (XLEED). Our XLEED system is operated at the primary electron current of about 0.1 pA, which minimizes the effect of desorption, defect formation, and charging. We observed the surface structure of Xe/Ag (111) by XLEED while monitoring the layer growth by the ellipsometry from a submonolayer film to a thick one. An equilibrium between the Xe film and coexisting three-dimensional Xe gas has been maintained throughout the experiment. From a monolayer film to a sufficiently thick film, the Xe overlayer has clear hexagonal structure whose directions of the unit vectors are coincident with those of the substrate. The Xe-Xe spacing in the monolayer film on Ag (111) is known to be a few per cent larger than that of bulk. Our interest is how the Xe-Xe spacing varies in the process of layer growth. We have made a systematic observation of the change of the Xe-Xe spacing in one and two monolayer films at pressures between 10^-7 and 10^-2 Pa and at temperatures between 50 and 100 K.

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Saturation coverages and adsorption energies of hydrogen molecules adsorbed at 4.2 K were investigated for several technical surfaces of an anodized aluminum, an electroplated copper coating and a sputtered TiZrV coating. From the result of adsorption isotherm measurements, the adsorbing molecules amount saturates in one monolayer, or two, on the smooth surfaces of the Cu and TiZrV coatings, while the adsorption capacity in the porous surface of the anodized aluminum is several tens times large. Thermal desorption spectra show the peak corresponding to the adsorption energy of about 20 meV for all the materials. In the anodized aluminum surface, when cleaned by baking, the additional sites with higher adsorption energies of 70 and 80 meV are observed. Hydrogen molecules adsorbs first in these sites, then forming an adlayer with the adsorption energy of 20 meV.

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Growth of GaN on sapphire (0001) substrates by metalorganic molecular beam epitaxy (MOMBE) was studied using triethyl gallium (TEGa) and rf plasma excited active nitrogen. A series of samples were grown under various TEGa flow rates while growth temperature (800°C) and nitrogen supply were fixed. With increasing TEGa flow rate, the dominant polytype of grown layer changed from hexagonal GaN (h-GaN) to cubic GaN (c-GaN). From the dependence of growth rate on TEGa flow rates, it was revealed that a Ga-stabilized growth condition results in the growth of c-GaN. This preferential growth mode was applied to the growth of c-GaN on cubic 3C-SiC (001) substrates.

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Oxygen mixed with nitrogen trifluoride (NF₃) was used for the gas source of the plasma etching to improve the etching rate of the polyimide (PI) film.
In order to investigate this etching mechanism, the etching products were analyzed with quadrupole mass spectrometer (QMS), and gas chromatography. From these analyses, main products were assumed to be H₂O, HF, CO, and CO₂. Moreover, the CO/CO₂ ratio was seemed to be related with etching rate depending on the NF₃ concentration. In the PI etching mechanism, the cracking process of the benzene rings is seemed to be important. There would be a rate-limiting step in the PI cracking with O₂ plasma. Formation of phenol groups would prevent breakdown of the benzene rings. On the other hand, this rate-limiting step would not exist in the breakdown process of benzene rings in the NF₃/O₂ plasma. The role of NF₃ is predicted to construct oxygen addition sites and reproduce oxygen which is an etchant of the PI.

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Attempts have been made to reveal a desirable design for a Ti/TiN multilayer as a protector for corrosion and wear at-tacks. Multilayers of Ti/TiN were deposited on two types of chromium molybdenum steels and on a high speed tool steel by switching on and off a reactive gas feed valve. Layer thicknesses were determined by scanning electron microscopy and also estimated from Ti depth profiles obtained by grow discharge atomic emission spectrometry (GD-AES). Corrosion resisitance was evaluated by two types of tests : one is the method where the coated steels were exposed to the gas generated through hydrolyzing a resin mixture of ABS and PVC at 443 K under a pressure of 2.87 MPa, and the other is the critical passivation current density method where a deaerated solution of 0.5 kmol/m³H₂SO₄-0.05 kmol/m³KSCN was used as an electrolyte. Ttribology tests were carried out under unlubricated conditions with a reciprocating type testing apparatus. Substrate current is a fairly useful indicator for precise control of layer thickness. GD-AES offers an exact estmation of layer thickness in the matter of minutes, for example, only within 0.4 ks for a multilayer of 56 μm in total thickness. Corrosion tests show that TiN coatings with a thicker Ti underlayer are more protective and that the multilayer coatings possess a better protective function when the ratio of cumulative thickness of Ti layers to that of TiN layers, ∑X_Ti to ∑X_TiN, is within 1 to 2. It is possible that an increase in thickness of the outer TiN layer brings about reduction of protection performance. With an increase in intrinsic compressive stress in the TiN layer, abrasive damage progresses more rapidly toward a substrate. The Ti layer contacting to the outer TiN layer suppressed the progression; for multilayers, therefore decreasing the thickness of the outer TiN layer resulted in a decrease in wear loss.

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