Abstract: A vapor growth apparatus forming a film on a substrate using a first source gas and a second source gas different form the first source gas, includes: a reaction chamber in which the substrate is disposed; a first source gas introduction path that communicates with the reaction chamber and introduces the first source gas; a second source gas introduction path that communicates with the reaction chamber and introduces the second source gas; and a separation gas introduction path that communicates with the reaction chamber between the first source gas introduction path and the second source gas introduction path and introduces a separation gas. The separation gas has a reaction rate with the first source gas and a reaction rate with the second source gas lower than the reaction rate between the first source gas and the second source gas.

Abstract: A semiconductor epitaxial wafer has, on a sapphire substrate, an AlN buffer layer formed of undoped AlN, a GaN buffer layer formed of 2 ?m-thick undoped GaN, and measurement electrodes formed thereon.