基于本实验室的实验条件,采用射频磁控溅射、等离子干法刻蚀等技术成功制备出具有ZnO∶Ga(GZO)透明电极的LED芯片。实验研究了相同工艺条件制备的ITO透明电极LED芯片和GZO透明电极LED芯片,对比实验结果表明GZO薄膜沉积工艺简单,其器件性能与ITO电极LED相当。相同条件下制备的GZO薄膜可见光波段透过率约90%,而ITO仅为75%。实验室制备的LED器件均具有较高的阈值电压,一方面p-GaN与ZnO的禁带宽度相差4.13 eV,接触势垒大,另一方面器件制备过程中的等离子体损伤薄膜表面和器件性能。
LED chips with ZnO∶Ga(GZO)transparent current spreading layer were prepared.Technologies such as RF magnetron sputtering and plasma dry etching were used in the experiments.Comparison of LED chips with ITO transparent current spreading layer were also made.What's more,chips with GZO electrode are almost the same as those with ITO electrode.Transmittance of GZO deposited by RF magnetron sputtering is as high as 90% in the visual spectral;in contrast,ITO deposited by DC magnetron sputtering is only about 75%.It seems that high transmittance conductive thin film is easier to be realized by GZO than ITO.However,chips made in the lab show high forward voltage(VF).Both of the band energy difference between p-GaN and ZnO and the damage made by plasma in the experiments contribute to the high forward voltage of the chips.