Ar流量对磁控溅射制备Al掺杂ZnO薄膜的影响

Al掺杂ZnO(AZO)具有电导率高、光学透射率高的优点,且原料来源丰富、制备成本低廉,被认为是最有应用潜力的透明导电薄膜。本文利用射频磁控溅射制备30 cm×30 cm尺寸大面积AZO薄膜,研究了气压恒定时,Ar流量对薄膜晶粒生长机制、电学和光学性能的影响。结果表明,AZO薄膜晶粒均表现出垂直基片方向的c轴择优取向生长,随Ar流量增大取向变弱;薄膜表面晶粒尺寸大小分布不均匀,随Ar流量增大,大晶粒数量增多,表面出现长度为100 nm、宽度为30 nm的棒状晶;随着Ar流量增大,载流子浓度由4.52×1020 cm-3略微增大至6.2×1020 cm-3,霍尔迁移率由4.79 cm2(/V·s)提升至10.46 cm2(/V·s),电阻率在Ar流量94 mL/min时达到最低值1.01×10-3Ω·cm。薄膜可见光平均透射率均大于78%,禁带宽度约3.8 eV。

Influence of Ar Flow Rate on Al-doped ZnO Thin Films Deposited by RF Magnetron Sputtering

Al-doped ZnO(AZO)has been considered to be one of the most potential transparent conductive oxides(TCO)due to its low cost,abundant and nontoxic feature.The AZO films with the area of 30 cm×30 cm were prepared by RF magnetron sputtering in this paper,and the influences of different Ar flow rate at the same working pressure on the mechanism of grain growth,electrical properties as well as optical properties of AZO thin films were studied in detail.All the AZO films showed c-axis orientation along the(002)plane preferred grain growth which was weakened by raising Ar flow rate.The films showed the inhomogeneous grain size distribution on the surface and the number of large size grain was increased by raising Ar flow rate.Some rod-like grains appeared on the surface with a length of 100 nm and width of 30 nm.The carrier concentration ofAZO films increased slightly from 4.52×1020 cm-3 to 6.2×1020 cm-3 while the hall mobility was improved substantially from 4.79 cm2/(V·s)to 10.46 cm2/(V·s).The minimum resistivity of 1.01×10-3Ω·cm was achieved when Ar flow rate was 94 mL/min.The average transmittance of more than 78%in the visible range is obtained for the samples and the band gap is estimated as 3.8 eV.