Optimization and Analysis of Magnesium Doping in MOCVD Grown p-GaN  

MOCVD生长的p型GaN薄膜中Mg掺杂的优化与分析(英文)

作　　者：张晓敏[1] 王彦杰[1] 杨子文[1] 廖辉[1] 陈伟华[1] 李丁[1] 李睿[1] 杨志坚[1] 张国义[1] 胡晓东[1] 

机构地区：[1]北京大学物理学院宽禁带半导体研究中心,人工微结构和介观物理国家重点实验室,北京100871

出　　处：《Journal of Semiconductors》2008年第8期1475-1478,共4页半导体学报（英文版）

基　　金：国家高技术研究发展计划(批准号:2007AA03Z403);国家重点基础研究发展计划(批准号:2007CB307004);国家基础研究计划(批准号:2006CB604908,2006CB921607);国家自然科学基金(批准号:60477011,60776042)资助项目~~

摘　　要：p-type conductivity and crystal quality of Mg-doped GaN grown by MOCVD have been improved through opti- mization of the magnesium flow rate. The hole concentration first increased and then decreased with the magnesium flow rate while the mobility decreased monotonously. The optimum sample reached a hole concentration of 4. 1×10^17cm -3 and a resistivity of 1Ω·cm. Based on a self-compensation model involving the deep donor Mo, VN, we calculate the hole con- centration as a function of magnesium doping concentration NA ,which indicates that the self-compensation coefficient in- creases with NA;the hole concentration first increases with NA and reaches a maximum at NA≈4×10^19 ,then decreases rapidly as doping concentration increases. XRD also indicate that dislocation density decreased as magnesium flow rate decreased.通过优化Mg流量增强了MOCVD生长的GaN薄膜的p型电导并改善了晶体质量.Hall测量结果表明空穴浓度首先随着Mg流量的升高而升高,达到极大值后开始降低;迁移率始终随Mg流量的升高而降低.最优的样品在室温下空穴浓度达到4.1×1017cm-3,电阻率降至1Ω.cm.考虑施主型缺陷MGaVN的自补偿作用,计算了空穴浓度随掺杂浓度变化的曲线关系.计算结果表明自补偿系数随掺杂浓度的增大而增大;空穴浓度首先随掺杂浓度的增大而增加,在受主浓度为NA≈4×1019左右时达到极大值,之后随着掺杂浓度的增大而迅速降低.XRD数据表明在实验范围内晶体缺陷密度随着掺杂浓度的降低而降低.

关 键 词：P-GAN self-compensations magnesium doping MOCVD 

分 类 号：TN304.23[电子电信—物理电子学]