Abstract: A method of implanting a magnetic garnet film with ions is disclosed in which a covering film is provided on a monocrystalline magnetic garnet film for magnetic bubbles, and hydrogen ions are implanted in a desired portion of a surface region in the magnetic garnet film through the covering film. According to this method, it is possible to form an ion-implanted layer in which the ion concentration distribution in the direction of depth is uniform, and moreover the inplane anisotropy field in the ion-implanted layer decreases only a little with time in an annealing process.

Abstract: A photomask is disclosed which is suitable for use in the one-mask method capable of forming a plurality of patterns with one exposure, and in which an opaque pattern having a predetermined form and a semi-transparent pattern having another predetermined form are formed on a transparent substrate, and the semi-transparent pattern is formed of an opaque film having a large number of fine through holes.

Abstract: A magnetic bubble memory device and a method of fabricating the device are disclosed in which a conductor pattern lies at least between a film for maintaining magnetic bubbles therein, and a soft magnetic material pattern. Further, the magnetic bubble memory device can be formed precisely without suffering from errors due to mask alignment, by employing a mask provided with a plurality of patterns which are different in transmittance.

Abstract: A method of forming a microscopic pattern wherein the object to be etched is overlaid with a film made of a material which is highly immune to etching and further provided with a reflection reducing film. Thus, the reflection of the irradiating ultraviolet rays by the underlying layer is effectively prevented.

Abstract: A magnetic bubble memory device is disclosed in which a hardened film made of a heat-resisting highly-polymerized organic resin and having a predetermined thickness is employed for an insulating film interposed between a conductor pattern and a soft magnetic material pattern. In a conventional magnetic bubble memory device in which the above-mentioned insulating film is made of SiO.sub.2, an abrupt step is produced in the soft magnetic material pattern due to the existence of the conductor pattern beneath a portion of the soft magnetic material pattern, and the margin of bias magnetic field is thereby lowered. According to the present invention, the step is reduced and smoothed, and thus the lowering of the margin can be prevented.

Abstract: Powdery alumina hydrate is produced from an alkylaluminum compound by hydrolysis of the alkylaluminum compound by water through the following steps; converting the alkylaluminum compound to an ether complex compound: partially hydrolyzing the ether complex compound in the presence of an non-reactive solvent at a temperature of not higher than about 150.degree.C with stirring so that no alumina hydrate is precipitated until at least 0.8 moles of water reacts with one mole of the alkylaluminum compound, thereby forming polyaluminoxane; completely hydrolyzing the resulting polyaluminoxane at a concentration of not more than about 3.0 grams-atoms as aluminum per liter of non-reactive solvent at a temperature of about 10.degree. to about 150.degree.C with stirring, so that one mole of the feed alkylaluminum compound may be ultimately hydrolyzed completely with 2 to 10 moles of water, thereby precipitating alumina hydrate; and then separating the resulting alumina hydrate from the non-reactive solvent.