SEMICONDUCTOR SUBSTRATE MANUFACTURING METHOD, SEMICONDUCTOR ELEMENT MANUFACTURING METHOD, SEMICONDUCTOR SUBSTRATE AND SEMICONDUCTOR ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor substrate manufacturing method which can reduce a concentration gradient of a carbon concentration in a high-resistance layer and make the carbon concentration be an intended value.SOLUTION: Provided is a manufacturing method of a semiconductor substrate which has a substrate, an initial layer on the substrate, a high resistance layer on the initial layer, which is composed of a nitride-based semiconductor and contains carbon, and a channel layer on the high resistance layer, which is composed of a nitride-based semiconductor. In a process of forming the high resistance layer, the high resistance layer is formed by generating a gradient of a preset temperature for heating the semiconductor substrate to make the preset temperature at the start of the high resistance layer formation be different from the preset temperature at the end of the high resistance layer formation.