中间退火对薄SiO_2膜电击穿特性的影响

EFFECTS OF INTERMEDIATE ANNEALING PROCESS ON ELECTRICAL BREAKDOWN CHARACTERISTICS OF THIN OXIDES

本文研究中间退火处理对薄SiO_2膜电击穿特性和高频电容-电压特性的影响。结果表明,在温度θ=950～1100℃和时间t=0～90分钟范围内,薄SiO_2膜的缺陷密度和固定电荷密度随中间退火温度升高和时间增长而减少。与常规后退火比较,中间退火能更有效地改善干氧氧化膜的电击穿特性,也能改善湿氧氧化膜和TCE氧化膜的电击穿特性。经中间退火处理的干氧氧化膜,其固定电荷密度也稍有降低。

In this paper the effects of intermediate annealing process on electrical breakdown properties and hight frequency capacitance- voltage characteristics of thin oxide films are studied.The exper- imental results show,That the defect density and fixed charge den- sity of thin oxide films decrease with the increase of the tempera- ture(from 950℃ to 1100℃)and time(from 0 to 90 minutes)in intermediate annealing treatment.Compared with the postoxidation annealing process,the intermediate annealing improves the electrical breakdown characteristics not only in dry oxygen oxidation,but also in wet-oxidation and TCE oxidation.However,the effectiven- ess in dry oxidation is superior to the other two,that is,wet-oxida- tion and TCE oxidation.Besides,the densities of fixed charge can also be reduced slightly in dry oxide films with intermediate anne- aling step.