干氧SiO2的氢氟酸缓冲腐蚀研究

根据对掺三氯乙烯(TCE)干氧氧化的SiO2在不同配比氢氟酸缓冲腐蚀液(BHF)中的腐蚀特性的研究结果表明, 在HF wt%保持不变的条件下,腐蚀速率先随着NH4F wt%的增大而上升;NH4F大于15wt%～20wt%以后,腐蚀速率反而随之降低.值得注意的是,干氧SiO2同湿氧SiO2相比,在1wt% HF条件下,前者的腐蚀速率要比后者高,直到HF酸浓度大于3wt%时,前者的腐蚀速率才低于后者,这一现象可用NH 4 阻挡模型结合TCE在SiO2中引入浅电子陷阱的方式得到解释.

Wet etching of dry thermal SiO2 with buffered hydrofluoride acid

Results of a study into the etching characteristics of dry thermal trichloroethylene-growth silicon dioxide in different compositions of buffered hydrofluoride acid(BHF) are presented.They indicate that when HF wt% is constant,the etch rate of SiO_2 increases as NH4F wt% increases,but will turn to decrease when the NH4F exceeds a weight percentage somewhere between 15wt%~20wt%.It is worth noticing that under the condition of HF 1wt% the etch rate of dry thermal SiO_2 is higher than wet-oxygen thermal silicon oxide.Only when HF>3wt%,the etch rate of dry thermal SiO_2 is lower than wet-oxygen thermal silicon oxide.This phenomenon can be explained by combining NH~+_4 blocking model with shallow electron traps introduced by TCE.