高介电氧化钽薄膜制备与介电性能分析

PREPARATION AND DIELECTRIC PROPERTIES ANALYSIS OF HIGH DIELECTRIC Ta_2O_5 THIN FILMS

在较低衬底温度下,通过磁控溅射得到的非晶态Ta2O5薄膜,在氧气氛750℃条件下进行化学热退火,得到晶化的Ta2O5薄膜,其相对介电常数为34.3,漏电流密度小于10-7A/cm2。电容量测试时,为了较好地消除高温退火时产生的SiO2的介质层对电容测试值的影响,用不同厚度氧化钽薄膜为介质层做成金属-绝缘体-金属(MIM)结构的电容器,对这些电容器的电容测试数据,进行Sigmoidal拟合,得到极限电容,从而计算出Ta2O5薄膜的介电常数。

The amorphous Ta2O5thin films were deposited by magnetron sputtering at low substrate temperature. By chemical thermal annealing at 750℃ in oxygen atmosphere, crystallized Ta2O5 thin films with relative dielectric constant of 34.3 and leakage current density of lower than 10-TA/cm^2 were obtained. In order to eliminate the influence of SiO2 dielectric layer introduced at high temperature annealing on the measurement of capacity, capacitors with the metal-insulator-metal structure were fabricated using Ta2O5thin films with different thickness as dielectric layer. The limit value of capacity was obtained based on Sigmoidal fitting of measured data, from which dielectric constant can be calculated.