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利用金属有机物化学气相淀积(MOCVD)生长了InGaN/GaN多量子阱(MQW)蓝光发光二极管(LED),研究了不同Cp2Mg流量下生长的p-GaN盖层对器件电学特性的影响。结果表明,随着Cp2Mg流量的提高,漏电流升高,并且到达一临界点会迅速恶化;正向压降则先降低,后升高。进而研究相同生长条件下生长的p-GaN薄膜的电学特性、表面形貌及晶体质量,结果表明,生长p-GaN盖层时,Cp2Mg流量过低,盖层的空穴浓度低,电学特性不好;Cp2Mg流量过高,则会产生大量的缺陷,盖层晶体质量与表面形貌变差,使得空穴浓度降低,电学特性变差。因此,生长p-GaN盖层时,为使器件的正向压降与反向漏电流均达到要求,Cp2Mg流量应精确控制。
InGaN / GaN multiple quantum well (MQW) blue light emitting diodes (LEDs) were grown by metal organic chemical vapor deposition (MOCVD), and the effect of p-GaN cap grown at different Cp2Mg flow rates on the device electrical properties was investigated. The results show that with the increase of Cp2Mg flow rate, the leakage current increases rapidly and reaches a critical point and deteriorates rapidly. The forward voltage drop decreases first and then increases. The electrical properties, surface morphology and crystal quality of the p-GaN films grown under the same growth conditions were studied. The results show that the Cp2Mg flow rate is too low, the hole concentration of the cap layer is low and the electrical characteristics are not Good; Cp2Mg flow is too high, it will have a large number of defects, the cover crystal quality and surface morphology worse, making the hole concentration decreases, the electrical characteristics of the worse. Therefore, the growth of p-GaN cap layer, in order to make the device forward voltage drop and reverse leakage current to meet the requirements, Cp2Mg flow should be precisely controlled.