岡本 邦人

From the viewpoint of the crystallographic contribution to the formation of columnar grain structure we investigated the incidence angle dependences of the columnar grain structure and the texture for iron films prepared at various deposition rates R. The films were vapor-deposited at incidence angles of 15 degrees, 30 degrees, 45 degrees and 65 degrees on glass substrates heated at 473 K. The X-ray analysis using the Schulz method revealed that there exist three kinds of texture: [100], type I [111] and type II [111] textures. From the observation using replica electron microscopy and the measurement of electrical resistivity, it was found that the two characteristics of the columnar grain structure (inclination and bundling of columnar grains) depend on the kind of texture irrespective of the incidence angle. For the films with type I [111] texture, the inclination angle and the degree of bundling of columnar grains take constant values with R at a given incidence angle. For the films with [100] or type II [111] texture, on the other hand, the inclination angle and the degree of bundling change markedly with R even if the incidence angle is constant. These changes in columnar grain structure with R depending on the kind of texture can be understood by considering the appearance of the {100} crystal habit.

The columnar grain structure in obliquely deposited Fe1-x-Co, (x = 0-1) films has been investigated magnetically by measuring the effective anisotropy field and the effective saturation magnetization. Films were vapor-deposited at an incidence angle of 65-degrees from normal on glass substrates kept at 473 K. The packing of the columnar grains was found to be sparse in the x range from 0.02 to 0.77, where the columnar grains clearly exhibit the {100} crystal habit. The columnar grains align in the direction perpendicular to the incidence plane for all compositions. The degree of alignment depends on the kind of texture. The crystallographic contribution to the formation of the columnar grain structure is discussed.

The compositional dependence of the columnar grain structure in Fe1-x-Cox(x=0-1) films has been investigated. The films were vapor-deposited at an incidence angle of 65-degrees on glass substrates kept at 473 K. The pressure during deposition was 2.7 x 10(-2) Pa. Reflection ellipsometry detected morphology changes at compositions of 0.02, 0.5, 0.77 and 0.9. The X-ray analysis and replica electron microscopy revealed that these four compositions correspond to the crystallographic changes. With increasing x, columnar grains change texture from type I [111] (110BAR) to [100] (010) at x=0.5 and the crystal structure from bcc to hcp at x=0.9; in the x range from 0.02 to 0.77 columnar grains clearly exhibit the crystal habit. On the basis of these results the crystallographic contribution to the formation of the columnar grain structure is discussed.

In order to examine the crystallographic contribution to the formation of the columnar grain structure, the texture and columnar grain structure in obliquely deposited Co1-x-Nix films (x = 0-1) have been investigated by using the X-ray Schulz method, reflection ellipsometry and replica electron microscopy. Films were vapour deposited on glass substrates kept at 213 and 333 K at an incidence angle of 60-degrees. Although there is no appreciable preferred orientation in films prepared at 333 K, the [0001] and [111] textures are observed in films prepared at 213 K. In accordance with the evolution of texture the growth direction of columnar grains deviates from the vapour beam direction towards the film normal and columnar grains form bundles along the direction perpendicular to the incidence plane. This fact is understood by considering the crystallographic enhancement of the adatom movement due to momentum.

In order to analyse quantitatively the columnar grain structure in obliquely deposited cobalt films two anisotropy fields H(k)(1) and H(k)(2), which originate from the shape anisotropy of columnar grains, were extracted from the total magnetic anisotropy. The cobalt films were vapor deposited at an incidence angle of 60-degrees onto glass substrates kept at 213 K. The pressure during deposition was 4.0 x 10(-3) Pa. On the basis of the model that the film is composed of rectangular parallelepiped crystallites the columnar grain structure has been analysed using extracted H(k)(1) and H(k)(2), and its formation mechanism is discussed.

The columnar grain structure of iron films obliquely deposited by sputtering at various argon gas pressures (5-20 Pa) was investigated by measuring the optical constants, the magnetic anisotropy and the {110} pole distribution and compared with that of iron films evaporated in argon gas atmospheres (8 x 10(-2)-2 Pa). The geometrical incidence angle was 45-degrees and the substrate temperatures T(s) were 393, 483 and 553 K. The results obtained were as follows. (1) At T(s) = 393 K with increasing pressure the packing of columnar grains becomes sparse and the bundling of columnar grains disappears. The change in the columnar grain structure is similar to that in evaporated films in spite of the different pressure range. (2) With increasing T(s) the change in the columnar grain structure with pressure becomes small and the similarity between sputtered and evaporated films diminishes. Replica electron microscopy provided visual evidence of these results.