氢氟酸和PSG牺牲层腐蚀的TDC模型

对不同结构,即直沟道结构、冒泡结构和组合沟道结构的氢氟酸牺牲层腐蚀进行了研究.以往的牺牲层腐蚀模型和实验结果不能很好地吻合.以往的模型和实验结果的误差随着腐蚀时间的增加而增大.本文提出了一个修正模型,在修正模型中：HF的扩散系数是浓度和温度的函数;腐蚀速率常数是温度的函数;此外还考虑了腐蚀产物对腐蚀过程的影响.对于组合沟道结构,对腐蚀前端形状的描述采用了一个新的数学模型.实验结果和以往的模型以及修正模型进行了对比,结果表明修正模型能够和实验结果吻合得很好.

TDC Model for PSG Sacrificial Layer Etching with Hydrofluoric Acid

HF etching of sacrificial layers with different structures,namely channel,bubble,and joint-channel,is studied.The existing model cannot fit the experimental data well.The error of etching rate between the existing model and the experimental data increases with etching time.A modified model considering the diffusion coefficient as a function of HF concentration and temperature is proposed.The etching rate coefficient as a function of temperature and the effect of reaction production are also considered in the modified model.For the joint-channel structure,a new mathematical model for the etching profile is also adopted.Experimental data obtained with channel,bubble,and joint-channel structures are compared with the modified model and the previous model.The results show that the modified model matches the experiments well.