鈹離子佈值鎂摻雜氮化鎵薄膜之快速熱退火效應研究

Abstract

快速熱退火（RTA）對於鈹離子佈值P型氮化鎵（GaN:Mg）之薄膜特性研究;本論文針對Be離子佈值GaN:Mg 進行了快速熱退火活化處理，並進行薄膜特性的量測，我們也探討快速升溫過程與高溫停留過程對薄膜的效應。 研究中發現，鈹離子佈值GaN後，經過1100℃, 15秒持續退火，已達電性活化的效果且P型載子濃度為2.4□1017 cm-3，但經過1100℃, 60秒持續退火產生薄膜結晶變差與Be相關缺陷，而使得電性被補償成為高阻值狀態，顯示了連續長時間高溫退火反而對薄膜特性有不良影響。而薄膜結晶度也隨著長時間的退火而變差。 我們以同樣經過1100℃ 60秒持續退火與4次1100℃ 15秒退火來研究快速升溫過程次數增加對於試片的影響。由PL光譜分析可發現，連續60秒持續退火造成明顯與Be相關複合物的深能階缺陷躍遷（~520nm）產生。在薄膜結晶方面，4次15秒退火亦較持續退火60秒的效果為佳。電性方面4次15秒退火有活化受體效果而60秒持續退火則使得試片成為高阻值狀態。表示了快速升溫過程次數增加對於薄膜的光、電、結晶性質有較佳的效果。 以相同的快速升溫過程次數，來研究不同的高溫停留時間對於薄膜所造成的影響。研究顯示高溫停留時間越長會產生Be相關的複合物缺陷光譜躍遷。

In this thesis, we realize the rapid thermal annealing (RTA) effect on Be implanted GaN:Mg, and investigate the ramping and the isothermal annealing effect of RTA process. In the study of the effect of RTA on Be implanted GaN:Mg. The optimum activation period range of single step annealing was from 15 to 40s and the films were activated as the p-type property with carrier concentration of about 2.4x 1017cm-3. The PL intensity of the Be-related defect peak (520nm) was increased by increasing the annealing period. The FWHM of GaN films was broadening by increasing annealing period from the X-Ray rocking curve spectra. Furthermore research, the ramping and isothermal annealing effect of RTA on Be implanted GaN:Mg were discussed. We compared the multiple steps annealing for four times of 15 sec each with single step annealing for one time of 60s at the same annealing temperature. The Be-related defect and thermal crystal damage were decreased as the ramping repetition time progressed. Fixing the times of ramping repetition process, the Be-related defect was reduced during the shorter isothermal annealing time.