Group iii-v nitride layer and method for producing the same

A Group III-V nitride layer belonging to hexagonal crystal formed by growing on a substrate having a different lattice constant, with the proviso that a substrate containing either Li or C as a principal constituent element is excluded,

• wherein the Group III-V nitride layer satisfies at least one of the following conditions (i) to (iv):
• (i) a growth-plane is a plane perpendicular to {0001} (hereinafter, referred to as a “nonpolar plane”) and a full width at half maximum b1 of angle dependence of X-ray diffraction intensity in a plane perpendicular to the growth-plane and parallel to c-axis [0001], upon X ray incident angle from a direction parallel to the growth-plane, satisfies the condition of 0.01°≦b1≦0.5°;
• (ii) a growth-plane is a nonpolar plane and a full width at half maximum b2 of angle dependence of a X-ray diffraction intensity in {0001} plane, upon X-ray incident angle from a direction parallel to the growth-plane, satisfies the condition of 0.01°≦b2≦0.5°;
• (iii) a growth-plane is a nonpolar plane, and when a diffraction plane is {1-100} plane or {11-20} plane which forms an angle of 60° or more and less than 90° with the growth-plane, a full width at half maximum b3 of angle dependence of X-ray diffraction intensity in the diffraction plane, upon X-ray incident angle from a direction parallel to a plane perpendicular to the diffraction plane and parallel to c-axis [0001], satisfies the condition of 0.01°≦b3≦0.5°;
• and
• (iv) a growth-plane is a nonpolar plane and when, assuming that the growth-plane orientation is represented by {ijk0}, a diffraction plane is {ijk2} plane tilted from the growth-plane only to [0001] and [000-1] directions, a full width at half maximum b4 of angle dependence of X-ray diffraction intensity in the diffraction plane, upon X-ray incident angle from a direction parallel to a plane formed by tilting {0001} plane by an angle equal to a tilt angle from the growth-plane to the diffraction plane in the same direction, satisfies the condition of 0.01°≦b4≦0.5°.

A process for growing a Group III-V nitride layer belonging to hexagonal crystal on a substrate having a different lattice constant, with the proviso that a substrate containing Li as a principal constituent element is excluded,

• the process comprising steps of:
• (a) providing a substrate having, as a principal surface, a hexagonal nonpolar plane or a plane having a lattice structure identical to that of the hexagonal nonpolar plane,
• (b) growing the Group III-V nitride layer on the principal surface of the substrate at least in two steps, comprising
• (b-1) a first sub-growing step of growing a first layer on the principal surface of the substrate at a growth temperature of lower than 500° C. while maintaining a single crystal structure on the growth-plane, and
• (b-2) a second sub-growing step of growing a second layer on the first layer at a growth temperature of 400° C. or higher and higher than the growth temperature in the first sub-growing step.

A Group III-V nitride layer belonging to hexagonal crystal formed by growing on a substrate having a different lattice constant,

• wherein
• the substrate is a ZnO substrate having a nonpolar plane as a principal surface,
• is grown by pulse laser deposition where a Group III element and nitrogen radicals are supplied, and
• has a composition represented by InxAlyGa(1-x-y)N wherein x and y are numbers satisfying the conditions of 0≦x≦1, 0≦y≦1 and 0≦x+y≦1, and
• wherein at least one of the following conditions (i) to (v) is met:
• (i) a growth-plane is a plane perpendicular to {0001} (hereinafter, referred to as a “nonpolar plane”) and a full width at half maximum b1 of angle dependence of X-ray diffraction intensity in a plane perpendicular to the growth-plane and parallel to c-axis [0001] upon X ray incident angle from a direction parallel to the growth-plane satisfies the condition of 0.01°≦b1≦0.5°;
• (ii) a growth-plane is a nonpolar plane and a full width at half maximum b2 of angle dependence of a X-ray diffraction intensity in {0001} plane upon X-ray incident angle from a direction parallel to the growth-plane satisfies the condition of 0.01°≦b2≦0.5°;
• (iii) a growth-plane is a nonpolar plane, and when a diffraction plane is {1-100} plane or {11-20} plane which forms an angle of 60° or more and less than 90° with the growth-plane, a full width at half maximum b3 of angle dependence of X-ray diffraction intensity in the diffraction plane upon X-ray incident angle from a direction parallel to a plane perpendicular to the diffraction plane and parallel to c-axis [0001] satisfies the condition of 0.01°≦b3≦0.5°;
• (iv) a growth-plane is a nonpolar plane and when, assuming that the growth-plane orientation is represented by {ijk0}, a diffraction plane is {ijk2} plane tilted from the growth-plane only to [0001] and [000-1] directions, a full width at half maximum b4 of angle dependence of X-ray diffraction intensity in the diffraction plane upon X-ray incident angle from a direction parallel to a plane formed by tilting {0001} plane by an angle equal to a tilt angle from the growth-plane to the diffraction plane in the same direction satisfies the condition of 0.01°≦b4≦0.5°;
• and
• (v) a growth-plane is a nonpolar plane and a full width at half maximum a1 of angle dependence of X-ray diffraction intensity of the growth-plane upon X-ray incident angle from a direction parallel to a plane perpendicular to the growth-plane and parallel with c-axis satisfies the condition of 0.01°≦a1≦0.25°.

A process for growing a Group III-V nitride layer belonging to hexagonal crystal on a substrate having a different lattice constant, with the proviso that a substrate containing Li as a principal constituent element is excluded,

• the process comprising growing steps of:
• (a) providing a substrate having a hexagonal nonpolar plane or a plane having a lattice structure identical to that of the hexagonal nonpolar plane,
• (b) growing the Group III-V nitride layer on the principal surface of the substrate at least in two steps, comprising
• (b-1) a first sub-growing step of growing a first layer on the principal surface of the substrate at a growth temperature of lower than 500° C. while intermittently supplying a Group III element with a supply stop period in the range of 0.001 sec to 10 sec, and
• (b-2) a second sub-growing step of growing a second layer on the first layer at a growth temperature of 400° C. or higher and higher than the growth temperature in the first sub-growing step.

A process for growing a Group III-V nitride layer belonging to hexagonal crystal on a substrate having a different lattice constant, with the proviso that a substrate containing Li as a principal constituent element is excluded,

• the process comprising the growing steps of:
• (a) providing a substrate having a hexagonal nonpolar plane or a plane having a lattice structure identical to that of the hexagonal nonpolar plane,
• (b) growing the Group III-V nitride layer on the principal surface of the substrate at least in two steps, comprising
• (b-1) a first sub-growing step of growing a first layer on the principal surface of the substrate at a growth temperature of lower than 500° C. and a growth rate of more than 10 nm/hr and less than 300 nm/hr while intermittently supplying a Group III element with a supply stop period in the range of 0.001 sec to 10 sec, and
• (b-2) a second sub-growing step of growing a second layer on the first layer at a growth temperature of 400° C. or higher and higher than the growth temperature in the first sub-growing step.