Abstract: A group III nitride crystal containing therein an alkali metal element comprises a base body, a first group III nitride crystal formed such that at least a part thereof makes a contact with the base body, the first group III nitride crystal deflecting threading dislocations in a direction different from a direction of crystal growth from the base body and a second nitride crystal formed adjacent to the first group III nitride crystal, the second nitride crystal having a crystal growth surface generally perpendicular to the direction of the crystal growth.

Abstract: A crystal growth method of a group III nitride includes the steps of forming a melt mixture of an alkali metal and a group III element in a reaction vessel, and growing a crystal of a group III nitride formed of the group III element and nitrogen from the melt mixture in the reaction vessel, wherein the step of growing the crystal of the group III nitride is conducted while controlling an increase rate of degree of supersaturation of a group III nitride component in the melt mixture in a surface region of the melt mixture.

Abstract: A crystal growth apparatus comprises a reaction vessel holding a melt mixture containing an alkali metal and a group III metal, a gas supplying apparatus supplying a nitrogen source gas to a vessel space exposed to the melt mixture inside the reaction vessel, a heating unit heating the melt mixture to a crystal growth temperature, and a support unit supporting a seed crystal of a group III nitride crystal inside the melt mixture.

Abstract: A crystal growth apparatus comprises a reaction vessel holding a melt mixture containing an alkali metal and a group III metal in a vessel space thereof, a porous member holding a metal melt by a surface tension thereof in a path through which a vapor of the alkali metal in contact with the metal mixture in the vessel space escapes to an external space, the porous member further supplying a nitrogen source gas fed from outside thereto further to the reaction vessel therethrough and through the metal melt by a pressure difference formed between the vessel space in the reaction vessel and the external space, and a heating apparatus heating the melt mixture to a crystal growth temperature.

Abstract: A crystal has a diameter of 1 cm or more and shows a strongest peak in cathode luminescent spectrum at a wavelength of 360 nm in correspondence to a band edge.

Abstract: In the case where an ultraminiature piezoelectric substrate, which has a resonating portion formed by making a concavity by etching in the surface of the piezoelectric substrate made of an anisotropic crystal material, is mass-produced by batch operation using a large-area piezoelectric substrate wafer, an annular portion surrounding each concavity is formed sufficiently thick to prevent cracking from occurring when the wafer is severed.

Abstract: In the case where an ultraminiature piezoelectric substrate, which has a resonating portion formed by making a concavity by etching in the surface of the piezoelectric substrate made of an anisotropic crystal material, is mass-produced by batch operation using a large-area piezoelectric substrate wafer, an annular portion surrounding each concavity is formed sufficiently thick to prevent cracking from occurring when the wafer is severed.

Abstract: A group-III nitride crystal growth method comprises the steps of: a) preparing a mixed molten liquid of an alkaline material and a substance at least containing a group-III metal; b) causing growth of a group-III nitride crystal from the mixed molten liquid prepared in the step a) and a substance at least containing nitrogen; and c) creating a state in which nitrogen can be introduced into the molten liquid prepared by the step a).

Abstract: The present invention provides a method for making high-frequency piezoelectric resonators so that constants of the resonator can be measured precisely. A cavity is formed at a central section of an AT-cut crystal substrate. Two grooves are formed at predetermined distances from the left and right of the cavity, and two more grooves are formed at predetermined distances outward from these two grooves. Two more grooves perpendicular to the first set of grooves are formed. A pair of main electrodes and a pair of secondary electrodes shorted to ground and surrounding the main electrodes are disposed at roughly the center of the crystal substrate. One main electrode and one secondary electrode are used as inputs and the other main electrode and secondary electrode are used as outputs, with these two terminal pairs being used to measure and adjust a frequency.

Abstract: The present invention provides a method for making high-frequency piezoelectric resonators so that constants of the resonator can be measured precisely. A cavity is formed at a central section of an AT-cut crystal substrate. Two grooves are formed at predetermined distances from the left and right of the cavity, and two more grooves are formed at predetermined distances outward from these two grooves. Two more grooves perpendicular to the first set of grooves are formed. A pair of main electrodes and a pair of secondary electrodes shorted to ground and surrounding the main electrodes are disposed at roughly the center of the crystal substrate. One main electrode and one secondary electrode are used as inputs and the other main electrode and secondary electrode are used as outputs, with these two terminal pairs being used to measure and adjust a frequency.

Abstract: A group-III nitride crystal growth method comprises the steps of: a) preparing a mixed molten liquid of an alkaline material and a substance at least containing a group-III metal; b) causing growth of a group-III nitride crystal from the mixed molten liquid prepared in the step a) and a substance at least containing nitrogen; and c) creating a state in which nitrogen can be introduced into the molten liquid prepared by the step a).

Abstract: A group-III nitride crystal growth method, comprising the steps of: a) preparing a mixed molten liquid of an alkaline metal and a material at least comprising a group-III metal; b) growing a group-III nitride crystal of the group-III metal and nitrogen from the mixed molten liquid and a material at least comprising nitrogen; and c) setting a predetermined crystal growth condition according to a zone defined by a pressure and a temperature in said step b).

Abstract: The present invention provides a method for making high-frequency piezoelectric resonators so that constants of the resonator can be measured precisely. A cavity is formed at a central section of an AT-cut crystal substrate. Two grooves are formed at predetermined distances from the left and right of the cavity, and two more grooves are formed at predetermined distances outward from these two grooves. Two more grooves perpendicular to the first set of grooves are formed. A pair of main electrodes and a pair of secondary electrodes shorted to ground and surrounding the main electrodes are disposed at roughly the center of the crystal substrate. One main electrode and one secondary electrode are used as inputs and the other main electrode and secondary electrode are used as outputs, with these two terminal pairs being used to measure and adjust a frequency.

Abstract: A method of growing a group III nitride crystal grows a group III nitride crystal from a solution in which an alkaline metal, a group III metal and nitrogen are dissolved, and includes, in the solution, a material which increases solubility of the nitrogen into the solution.

Abstract: In the case where an ultraminiature piezoelectric substrate, which has a resonating portion formed by making a concavity by etching in the surface of the piezoelectric substrate made of an anisotropic crystal material, is mass-produced by batch operation using a large-area piezoelectric substrate wafer, an annular portion surrounding each concavity is formed sufficiently thick to prevent cracking from occurring when the wafer is severed.

Abstract: A crystal growth method of a group III nitride includes the steps of forming a melt mixture of an alkali metal and a group III element in a reaction vessel, and growing a crystal of a group III nitride formed of the group III element and nitrogen from the melt mixture in the reaction vessel, wherein the step of growing the crystal of the group III nitride is conducted while controlling an increase rate of degree of supersaturation of a group III nitride component in the melt mixture in a surface region of the melt mixture.

Abstract: The present invention provides a method for making high-frequency piezoelectric resonators so that constants of the resonator can be measured precisely. A cavity is formed at a central section of an AT-cut crystal substrate. Two grooves are formed at predetermined distances from the left and right of the cavity, and two more grooves are formed at predetermined distances outward from these two grooves. Two more grooves perpendicular to the first set of grooves are formed. A pair of main electrodes and a pair of secondary electrodes shorted to ground and surrounding the main electrodes are,disposed at roughly the center of the crystal substrate. One main electrode and one secondary electrode are used as inputs and the other main electrode and secondary electrode are used as outputs, with these two terminal pairs being used to measure and adjust a frequency.

Abstract: Disclosed is a piezoelectric resonator that has a piezoelectric plate that has formed thereon a pair of main electrodes and has formed thereon a second electrode surrounding the peripheral edge of the main electrode with a gap being provided between the second electrode and a peripheral edge of the main electrode. The material of the main electrode and the material of the second electrode are differentiated from each other. As the material of the second electrode there is used a material the density of that is lower than the material of the main electrode. With this construction, there is obtained means for suppressing the occurrence of spurious due to an inharmonic mode generating in the high frequency piezoelectric resonator.

Abstract: A method of making a bulk crystal substrate of a GaN single crystal includes the steps of forming a molten flux of an alkali metal in a reaction vessel and causing a growth of a GaN single crystal from the molten flux, wherein the growth is continued while replenishing a compound containing N from a source outside the reaction vessel.

Abstract: A group-III nitride crystal growth method, comprising the steps of: a) preparing a mixed molten liquid of an alkaline metal and a material at least comprising a group-III metal; b) growing a group-III nitride crystal of the group-III metal and nitrogen from the mixed molten liquid and a material at least comprising nitrogen; and c) setting a predetermined crystal growth condition according to a zone defined by a pressure and a temperature in said step b).