摘要
使用 CO2 、O2 氧源得到了 Zn O择优取向薄膜样品 ,实验证实了小尺寸的交流高压离化器件确实能够为低压金属有机物化学气相沉积 (L P- MOCVD)生长 Zn O薄膜提供有效的离化氧源支持 .运用电晕放电模型和 Zn O薄膜台阶生长模型研究了离化效率对电压、气压和不同氧源气体的依赖关系及负氧浓度对生长速率和薄膜质量的影响 .对 X射线衍射谱、光致发光谱、原子力显微镜和俄歇电子能谱的分析表明 ,CO2 氧源由于离化效率较高 ,负氧浓度较大 ,使得生长速率较慢 ,薄膜表面较为平坦 ,但表面 C污染影响了薄膜内部质量 ;而 O2 氧源样品取向更接近(0 0 0 2 )衬底取向 ,样品内部应力较小 ,晶格常数更接近正常化学配比的 Zn O单晶 ,这表明最优负氧浓度的存在和气源带来的污染是 Zn O生长中必须考虑的问题 .
The experiment proves that plasma ionizing in different oxidants is critically important for depositing the ZnO film.High quality c axis oriented single crystal films are grown using CO 2 and O 2 as oxidant,respectively.The ionizing efficiency as a function of the exciting potential,pressure for different oxidant gases is calculated.The influences of the concentration of oxygenic ions on the deposition velocity and growth quality are studied theoretically by the step flow model.Due to the results of XRD,PL,AFM and AES,high ionizing efficiency of CO 2 oxidant gives S1 sample exhibits a lower growth rate and smoother surface.While sample S2,which uses O 2 as its oxidant,obtains high structure properties.This confliction reveals the unavoidable problem of the nonlinear optimization of film properties with respect to the concentration of oxidant ions and contaminations introduced by oxidants.
