PMMA分子量对其电学特性的影响

The effect of Molecular weight on the electrical property of PMMA

通过分析以PMMA[poly(methyl methacrylate)]为绝缘膜的MIS结构的电学特性,研究了分子量对PMMA薄膜电学特性的影响。PMMA薄膜通过旋涂溶于氯仿的20mg/ml PMMA溶液制成。PMMA薄膜厚度为220nm,临界电场超过1.8MV/cm。测量结果表明:(1)996K分子量PMMA薄膜的单位面积漏电流最小,仅有6.0×10-9/cm2。350K分子量的漏电流较大,为8.5×10-9/cm2;(2)高电场下决定漏电流与场强关系的物理机制是肖特基发射,通过线性拟合计算出银电极与PMMA之间的势垒高度约为0.5eV;(3)分子量大的PMMA陷阱密度小。996K分子的最小,为4.7×1010/cm2。

In this paper we present a detailed characterization of metal-insulator-semiconductor MIS structure with PMMA as insulator layer.The effect of molecular weight on the electrical property of PMMA is researched.The PMMA layer is spin coated from a 20mg/ml dilution of PMMA in chloroform.The critical electric field is more than 1.8MV/cm and the thickness is 220nm.When the molecular is 996K,we get the minimum unit area current,which is 6.0×10-9A/cm2.While the molecular is 350K,we get bigger unit area current,which is 8.5×10-9/cm2.Schottky emission accounts for the leakage current versus electric field strength behavior in high electric fields and the Schottky barrier height is 0.9eV calculated by linear fitting.The trap density decreases with the molecular weight increasing.996k molecular weight PMMA has the least trap density,which is 4.7×1010/cm2.