ALD氧化铝薄膜介电性能及其在硅电容器的应用

Dielectric Property of ALD Al_2O_3 Film and its Application in Silicon Capacitor

硅基高密度电容器是利用半导体3D深硅槽技术和应用高介电常数(高K)材料制作的电容。相比钽电容和多层陶瓷电容(MLCC),硅基电容具有十年以上的寿命、工作温度范围大、容值温度系数小以及损耗低等优点。文章研究原子层沉积(ALD)制备的Al2O3薄膜的介电特性,通过优化ALD原子沉积温度和退火工艺,发现在沉积温度420℃和O3气氛退火5 min下,ALD生长的Al2O3薄膜击穿强度可大于0.7 V/nm,相对介电常数达8.7。制成的硅基电容器电容密度达到50 nF/mm2,漏电流小于5 nA/mm2。

Silicon high density capacitor is a capacitor made with semiconductor silicon 3D deep trench technology and high dielectric constant （high K） material. Compared with tantalum capacitor and multi- layer ceramic capacitor, silicon capacitor has more than 10 years long lifetime, extreme working temperature range, low temperature coefficient and low energy consumption. In this paper, the dielectric property ofAl203 film grown by atomic layer deposition were studied. By the optimization of deposition temperature and annealing parameters, it was found that the breakdown field of the AI203 film is large than 0.7 V/nm and the relative permittivity is 8.7 when the film was grown at 420 ~C and annealed in 03 5 minutes. The capacitance density of the silicon capacitor has reached 50 nF/mm2 and the leakage current is less than 5 nA/mmL Key words： silicon capacitor; A1203; deep trench; dielectric property; atomic layer deposition