NITRIDE-BASED COMPOUND SEMICONDUCTOR WAFER, NITRIDE- BASED COMPOUND SEMICONDUCTOR ELEMENT AND GROWTH OF NITRIDE-BASED COMPOUND SEMICONDUCTOR CRYSTAL

摘要

PROBLEM TO BE SOLVED: To obtain a nitride-based compound semiconductor wafer having a smooth surface of re-crystallization growth by providing a second nitride-based compound semiconductor layer that is grown at the temperature lower than the growth temperature of the nitride-based compound semiconductor layer between the nitride-based compound semiconductor layer and its growth layer. SOLUTION: A growth layer of undoped GaN is grown with the MOCVD method on a sapphire substrate. In this case, supply of the raw material gas to the growth layer is started at the temperature of 760 deg.C and is continued until the temperature becomes 1100 deg.C. Thereafter, GaN is grown again to manufacture the predetermined GaN crystal body. The surface condition of the GaN crystal re-grown on this growth layer is flat not including uneven surface because since the raw material gas is supplied in the stage of 760 deg.C which is so far lower than the crystal re-growth temperature, the second GaN layer is formed on the growth layer before the growth layer starts thermal decomposition and the GaN layer grows continuously after the re-growth temperature reaches 1100 deg.C and thereby any projection is no longer generated.