Abstract: This invention relates to a photosensitive polyimide material having positive-type or negative-type photosensitivity, which may be developed with a high resolution with an irradiation energy having short wavelength such as ultraviolet light or electron beam. The positive-type photosensitive polyimide composition comprising a solvent-soluble polyimide which shows positive-type photosensitivity in the presence of a photoacid generator, which is obtained by polycondensation of at least one aliphatic tetracarboxylic dianhydride and/or alicyclic tetracarboxylic dianhydride and at least one aliphatic diamine and/or alicyclic diamine and/or diaminosiloxane; and the photoacid generator. Since the polyimide has negative-type photosensitivity when irradiated with electron beam in the absence of a photoacid generator, a method for forming negative-type polyimide pattern using the polyimide is also provided.

Abstract: A method for controlling the thickness of a thin crystal film which is grown in a vacuum atmosphere, comprising the steps of: generating an electron beam in the vacuum atmosphere; directing the electron beam thus generated to a crystal being grown to obtain a diffraction pattern of the crystal; detecting the variations in time of the intensity of the diffraction pattern thus obtained; obtaining the number of oscillations from the variations thus detected; and interrupting the growth of the crystal in synchronism with the oscillations of the intensity when the number reaches a predetermined number. The composition ratio of a mixed crystal can be also determined by the ratio among the frequency of oscillations of each crystal which constitutes the mixed crystal. The oscillations of the intensity of the RHEED pattern can be observed more than 400 times so that the thickness of the grown thin crystal film can be measured with the accuracy higher than 1000 .ANG. in terms of the mono-layer.

Abstract: In the manufacture of a superlattice by the MBE method, growth of an epitaxial film on a growth substrate is accomplished by disposing a P-type and an N-type impurity evaporation source at positions adjacent to a main evaporation source and symmetrical to each other relative to the main evaporation source and causing the molecular beams issuing from these evaporation sources to be projected through a mask onto the growth substrate. When the apparatus used for the aforementioned growth of the epitaxial film is additionally provided with a shutter adapted to open and close at least one of the impurity evaporation sources, the projections of the molecular beams can be controlled so as to produce an interdigital periodic structure element.

Abstract: Disclosed is a solar battery comprising a multi-layered "p-n" junction structure, which has a plurality of inwardly converging recesses to partially expose the inner "p-n" junctions to the sun light.