A film structure comprises a substrate and a buffer film formed on the substrate. The substrate is a 36° to 48° rotated Y-cut Si substrate, or the substrate is a SOI substrate including a base substance made of the 36° to 48° rotated Y-cut Si substrate, an insulating layer on the base substance, and a SOI layer made of a Si film on the insulating layer, and a mirror index of a crystal plane of an upper surface of the SOI layer is equal to a mirror index of a crystal plane of an upper surface of the base substance. The buffer film includes ZrO.sub.2 epitaxially grown on the substrate.

A piezoelectric member that achieves a high sound speed includes a silicon-containing substrate and a piezoelectric layer. The piezoelectric layer is disposed on the silicon-containing substrate. At least a surface layer of the piezoelectric layer on a side opposite to the silicon-containing substrate is made of B.sub.xAl.sub.1-xN (0<x≦0.2).

Provided is a dielectric thin film including a metal oxide. The metal oxide includes bismuth, sodium, barium, and titanium, at least a part of the metal oxide is a tetragonal crystal having a perovskite structure, and a (100) plane of at least a part of the tetragonal crystal is oriented in a normal direction do of a surface of the dielectric thin film 3.

The present invention provides an epitaxial film forming method for epitaxially growing a high-quality group III nitride semiconductor thin film on an α-Al.sub.2O.sub.3 substrate by a sputtering method. In the epitaxial film forming method according to an embodiment of the present invention, when an epitaxial film of a group III nitride semiconductor thin film is to be formed on the α-Al.sub.2O.sub.3 substrate arranged on a substrate holder provided with a heater electrode and a bias electrode of a sputtering apparatus, in a state where the α-Al.sub.2O.sub.3 substrate is maintained at a predetermined temperature by the heater electrode, high-frequency power is applied to a target electrode and high-frequency bias power is applied to a bias electrode and at that time, the powers are applied so that frequency interference between the high-frequency power and the high-frequency bias power does not occur.

The present invention provides an epitaxial film forming method for epitaxially growing a high-quality group III nitride semiconductor thin film on an α-Al.sub.2O.sub.3 substrate by a sputtering method. In the epitaxial film forming method according to an embodiment of the present invention, when an epitaxial film of a group III nitride semiconductor thin film is to be formed on the α-Al.sub.2O.sub.3 substrate arranged on a substrate holder provided with a heater electrode and a bias electrode of a sputtering apparatus, in a state where the α-Al.sub.2O.sub.3 substrate is maintained at a predetermined temperature by the heater electrode, high-frequency power is applied to a target electrode and high-frequency bias power is applied to a bias electrode and at that time, the powers are applied so that frequency interference between the high-frequency power and the high-frequency bias power does not occur.

Methods of passivating at least one facet of a multilayer waveguide structure can include: cleaning, in a first chamber of a multi-chamber ultra-high vacuum (UHV) system, a first facet of the multilayer waveguide structure; transferring the cleaned multilayer waveguide structure from the first chamber to a second chamber of the multi-chamber UHV system; forming, in the second chamber, a first single crystalline passivation layer on the first facet; transferring the multilayer waveguide structure from the second chamber to a third chamber of the multi-chamber UHV system; and forming, in the third chamber, a first dielectric coating on the first single crystalline passivation layer, in which the methods are performed in an UHV environment of the multi-chamber UHV system without removing the multilayer waveguide structure from the UHV environment.

Quality of a silicon carbide single crystal is improved. A crucible having first and second sides is prepared. A solid source material for growing silicon carbide with a sublimation method is arranged on the first side. A seed crystal made of silicon carbide is arranged on the second side. The crucible is arranged in a heat insulating container. The heat insulating container has an opening facing the second side. The crucible is heated such that the solid source material sublimes. A temperature on the second side is measured through the opening in the heat insulating container. The opening has a tapered inner surface narrowed toward the outside of the heat insulating container.

A method is disclosed for producing a high quality bulk single crystal of silicon carbide in a seeded growth system by reducing the separation between a silicon carbide seed crystal and a seed holder until the conductive heat transfer between the seed crystal and the seed holder dominates the radiative heat transfer between the seed crystal and the seed holder over substantially the entire seed crystal surface that is adjacent the seed holder.

A method for growth and fabrication of semipolar (Ga,Al,In,B)N thin films, heterostructures, and devices, comprising identifying desired material properties for a particular device application, selecting a semipolar growth orientation based on the desired material properties, selecting a suitable substrate for growth of the selected semipolar growth orientation, growing a planar semipolar (Ga,Al,In,B)N template or nucleation layer on the substrate, and growing the semipolar (Ga,Al,In,B)N thin films, heterostructures or devices on the planar semipolar (Ga,Al,In,B)N template or nucleation layer. The method results in a large area of the semipolar (Ga,Al,In,B)N thin films, heterostructures, and devices being parallel to the substrate surface.

In one instance, the invention provides a bulk crystal of group III nitride having a thickness of more than 1 mm without cracking above the sides of a seed crystal. This bulk group III nitride crystal is expressed as Ga.sub.x1Al.sub.y1In.sub.1-x1-y1N (0≦x1≦1, 0≦x1+y1≦1) and the seed crystal is expressed as Ga.sub.x2Al.sub.y2In.sub.1-x2-y2N (0≦x2≦1, 0≦x2+y2≦1). The bulk crystal of group III nitride can be grown in supercritical ammonia or a melt of group III metal using at least one seed crystal having basal planes of c-orientation and sidewalls of m-orientation. By exposing only c-planes and m-planes in this instance, cracks originating from the sides of the seed crystal are avoided.