Stress and deformation of PZT thin films deposited on silicon wafers due to thermal expansion during the annelaing process are modeled using a 3-D shell element of ANSYS. Two different designs of PZT thin films on the wafer are modeled. The first design is a PZT/Pt/Ti/silicon dioxide/silicon wafer, which is used for making acoustic emission sensors. The second design is a PZT/Pt/Ti/silicon dioxide/silicon nitride/silicon dioxide/silicon wafer, commonly used in fabrication of cantilever beams. For the design without the silicon nitride layer, the themal stress of the PZT film is 298MPa, Pt 1280MPa, Ti 647MP, the silicon dioxide layer is 228MPa, and the silicon wafer is 0.41-1.67MPa. For the design with silicon nitride, the thermal stresses are: PZT 301 MPa, Pt 1280MPa, Ti 65MPa, silicon dioxide 226MPa, silicon nitride 416MPa,silicon dioxide 226MPa, and silicon wafer 1.05-4.23MPa. The residual stress of the PZT film is measured at 200-250MPa for the design without silicon nitride, and 336MPa for the design with silicon nitride. OCmparisons of the thermal stress with the tensile or proof stress of material for each layer indicate that thermal stress of the PZT film is slightly greater than its bulk tensile stress, the of Pt film is five greater than its bulk tensile stress, and that of Ti film s approximately equal to its bulk tensile stress. The thermal stresses of silicon dioxide, silicon nitride, and silicon wafer layersd are far smaller than their proof stresses.
展开▼
机译：使用ANSYS的3-D壳单元对在退火过程中由于热膨胀而沉积在硅晶片上的PZT薄膜的应力和变形进行建模。对晶片上的两种不同设计的PZT薄膜进行了建模。第一种设计是PZT / Pt / Ti /二氧化硅/硅晶片，用于制造声发射传感器。第二种设计是PZT / Pt / Ti /二氧化硅/氮化硅/二氧化硅/硅晶片，通常用于制造悬臂梁。对于没有氮化硅层的设计，PZT膜的热应力为298MPa，Pt 1280MPa，Ti 647MP，二氧化硅层为228MPa，硅晶片为0.41-1.67MPa。对于使用氮化硅的设计，热应力为：PZT 301 MPa，Pt 1280MPa，Ti 65MPa，二氧化硅226MPa，氮化硅416MPa，二氧化硅226MPa和硅片1.05-4.23MPa。对于没有氮化硅的设计，PZT膜的残余应力测量为200-250MPa，对于具有氮化硅的设计，测量为336MPa。每层材料的热应力与材料的拉伸应力或屈服应力之间的比较表明，PZT薄膜的热应力略大于其整体拉伸应力，Pt薄膜的热应力比其整体拉伸应力大五倍，而Ti膜s大约等于其整体拉伸应力。分层的二氧化硅，氮化硅和硅晶片的热应力远小于其屈服应力。
展开▼
