不同气体退火La_2O_3栅介质Ge MOS电容的电特性

Electrical Properties of Ge MOS Capacitors with La_2O_3 Gate Dielectric Annealed in Different Gases

采用电子束蒸发方法,在Ge衬底上淀积La_2O_3高k栅介质,研究了O_2、NO、NH_3和N_2不同气体退火对MOS电容电特性的影响。测量了器件的C-V和I-V特性,并进行了高场应力实验。结果表明La_2O_3在N_2气氛中退火后,由于形成稳定的LaGeO_x而有效地降低了Q_(ox)和D_(it),从而获得低的栅极漏电流,同时获得较高的栅介质介电常数(18)。

Ge MOS capacitors with La2O3 as gate dielectric are fabricated by e-beam evaporation of La2o3. Effects of post-deposition annealing in different gases （O2, NO, NH3, and N2） on electrical properties of MOS capacitors are investigated. The C-V and I-V characteristics of the device are measured, and a high-field stress is also performed to examine the reliability of the de- vices. Experimental results indicate that the sample annealed in N2 exhibits not only larger k value （18）, but also smaller Qox and Dit due to formation of the stable LaGeOX by the N2 annealing.