US 2026/0110112 A1Published application

N-type gan substrate and n-type gan crystal

AssigneeMitsubishi Chemical Corporation

InventorsTatsuya TAKAHASHI, Yuuki ENATSU, Takuya HIROSAWA

Life of this patent

Estimating the term…

Loading patent…

Abstract

An n-type GaN substrate having two main surfaces, the n-type GaN substrate being doped with Ge, having an average carrier concentration of 1×1018 cm−3 or more, and satisfying at least one selected from the group consisting of (1) to (3) when carrier concentrations are measured at measurement points uniformly provided in a circular region having a radius of 15 mm from the center of at least one main surface: (1) a standard deviation/average of measured values at measurement points on straight lines passing through the center of the main surface in directions of 0 degrees, 45 degrees, 90 degrees, and 135 degrees is 0.25 or less; (2) the ratio of the number of measurement points at which a carrier concentration is 2×1018 cm−3 or more to the total number of the measurement points is 90% or more; and (3) the ratio of the number of measurement points at which a measured value is (A) 60% or less/(B) 50% or less/(C) 40% or less of the maximum of measured values at all measurement points to the total number of the measurement points is (A) 10% or less/(B) 9% or less/(C) 8% or less. The n-type GaN substrate has a high carrier concentration and a uniform in-plane carrier concentration distribution.

An n-type GaN substrate comprising two main surfaces, the n-type GaN substrate

comprising Ge as a donor impurity,
having an average carrier concentration of 1×1018 cm−3 or more, and
satisfying at least one selected from the group consisting of (1), (2), and (3) below when
on at least one of the two main surfaces,
a line segment (line segment A) having a length of 30 mm is defined to have a midpoint that coincides with a center of the main surface;
a line segment (line segment B) having a length of 30 mm is defined to have a midpoint that coincides with the center of the main surface and to be orthogonal to the line segment A;
among square grid points provided at intervals of 0.5 mm with respect to the line segment A and the line segment B serving as two axes, the square grid points located in a circular region having a radius of 15 mm from the center of the main surface are used as measurement points;
and
carrier concentrations are measured at the measurement points:
(1) an average and a standard deviation of carrier concentrations at all measurement points on the line segment A, the line segment B, and two line segments that are bisectors of angles formed by the line segment A and the line segment B satisfy Formula (i) below:
standard deviation/average≤0.25 (i);
(2) a ratio of the number of measurement points at which a carrier concentration is 2×1018 cm−3 or more to the total number of the measurement points is 90% or more;
and
(3) at least one selected from the group consisting of conditions (A), (B), and (C) below is satisfied:
(A) a ratio of the number of measurement points at which a measured value is 60% or less of the maximum of measured values at all measurement points to the total number of the measurement points is 10% or less;
(B) a ratio of the number of measurement points at which a measured value is 50% or less of the maximum of measured values at all measurement points to the total number of the measurement points is 9% or less;
and
(C) a ratio of the number of measurement points at which a measured value is 40% or less of the maximum of measured values at all measurement points to the total number of the measurement points is 8% or less.

15 more elements

Abstract

Claims15