MOCVD Growth of Wide-bandgap Nitride Semiconductors

Following topics are reviewed in this paper. After an introduction in section 1, section 2 reviews growth conditions of the most widely used III-nitride semiconductors, GaN and InGaN, by mean of MOCVD, and their optical properties are examined in conjunction with the carrier localization and the quantum confined Stark effects. A-face sapphire is now collecting more attention as a substrate for electronic devices, since it is available in very large size. The growth on A-face sapphire substrate is reviewed in section 3. Several MOCVD reactors with large capacity available on market are introduced in section 4. Both negative and positive aspects of the dislocation in GaN and InGaN are summarized in section 5. Although a dislocation works as a non-recombination center, it produces indium composition fluctuation of an InGaN and enhances carrier localization making light emission efficiency less sensitive to the presence of non-radiative recombination centers. Section 6 summarizes new technique to reduce dislocation density in GaN grown on heterogeneous substrates. And the paper is summarized in section 7.