HVPE GaN生长中TiN网栅的制备和作用  

Preparation and Effect of TiN Mask During the Growth of GaN Wafers by Hydride Vapor Phase Epitaxy

作　　者：张嵩 齐成军 王再恩 孙科伟 Zhang Song;Qi Chengjun;Wang Zaien;Sun Kewei(The 46＇h Research Institute, CETC, Tianjin 300220, China)

机构地区：[1]中国电子科技集团公司第四十六研究所

出　　处：《微纳电子技术》2018年第10期768-774,共7页Micronanoelectronic Technology

摘　　要：利用退火工艺在MOCVI）_GaN基片表面制作TiN网栅，同时基片可形成疏松的多孔GaN结构。退火过程中温度越高、氢气分压越大，所形成的孔隙越大越深。高温下GaN分解的Ga因与H结合成为气相而使多孔结构沟槽内无残余Ga滴，可作为之后GaN外延的成核位置，未被刻蚀部分表面被TiN薄膜覆盖。采用HVPE方法在具有多孔结构的GaN基片上进行30min生长后，原有孔洞会被部分长合，而由于上层GaN的N面高温热解，形成新孔洞层，从而在降温过程起到释放热应力的作用，改善了GaN的结晶质量，位错密度可以降低至5×106cml以下。The TiN mask on the surface of the MOCVD-GaN template was prepared by annealing process, and the porous GaN structure was formed on the template at the same time. The formed voids became larger and deeper with the increases of the temperature and partial pressure of H2 during the annealing process. For the combination of H and Ga generated by the decomposition of GaN, Ga turned to gas phase at high temperatures and no residual Ga droplets were found in the porous grooves which can be the nucleation position of （;aN in the epitaxy process later. The unetched parts of the template were covered by TiN thin films. Subsequently, the original voids were partially covered after the porous GaN template was grown with the hydride vapor phase epitaxy （HVPE） method for 30 min. During the process, new voids layer generated from the de- composition of the N-polar face on the top of GaN at high temperatures. As a result, the voids layer can release the thermal stress during the cooling process and the crystallization quality is im- proved with the dislocation density reduced less than 5 x 106 cm-2.

关 键 词：MoCVD—GaN TiN网栅 多孔GaN 退火 氢化物气相外延(HVPE) 热应力 

分 类 号：TN304.054[电子电信—物理电子学] TN304.23