Study on the sintering and contact formation process of silver front side metallization pastes for crystalline silicon solar cells
Study on the sintering and contact formation process of silver front side metallization pastes for crystalline silicon solar cells
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DOI：
10.1016/j.apsusc.2016.03.089
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发表时间：
2016-07-15
影响因子：
6.7
通讯作者：
Liu, Zhuofeng
中科院分区：
文献类型：
--
作者：
Qin, Jun;Zhang, Weijun;Liu, Zhuofeng
通过中断不同温度下的烧成，研究了含浆料的PTO玻璃的烧结过程和接触形成过程。采用原子力显微镜/扫描电子显微镜(FIB/SEM)技术研究了PTO玻璃浆料间歇烧成接触指的显微结构，并对浆料的烧结过程进行了研究。浆体的烧结过程可分为三个阶段，分别为初始阶段、中间阶段和最终阶段。只有在烧结的初期和中期，含银玻璃相才能通过Ag颗粒之间的连续孔道向下流动到Ag/Si界面，这是因为在烧结的最后阶段，Ag的致密性很强。玻璃相流动过程与银致密化过程的极大不协调会导致大量玻璃滞留在致密银层中，从而导致硅片刻蚀不均匀。在较低的烧成温度下，可以在界面玻璃相中观察到银的析出。在相对较高的温度下，随着界面玻璃相中Ag析出物数量的减少，镶嵌在硅发射极中的Ag微晶出现。较低的粘度和较高的界面玻璃相离子扩散速度会使银微晶在较低的温度下出现。随着烧结温度的升高，界面玻璃层厚度的增加和银晶的异常长大，以及银析出物数量的减少，导致了接触电阻的增加。(C)2016爱思唯尔B.V.保留所有权利。
In the paper, sintering process and contact formation process of PTO glass containing pastes were studied by interrupting the firings at different temperatures. Microstructures of contact fingers fabricated using pastes with PTO glass by interrupted firings were obtained by FIB/SEM technology and the sintering process of pastes was studied. The sintering process of pastes can be divided into three stages, the initial stage, intermediate stage and final stage, respectively. Only during the initial stage and intermediate stage of sintering, Ag-containing glass-phase is able to flow downward to the interface of Ag/Si through the continuous pore channels between Ag particles due to the great densification of Ag in the final stage of sintering. The great disharmony between the flow process of glass-phase and Ag densification would cause much glass trapped in densified Ag and thereby non-uniform etching of Si wafers.Contact formation process of pastes was studied by observing the Ag contact and Si emitter interface. Ag precipitates can be observed in the interfacial glass-phase at low firing temperature. Ag crystallites embedded in Si emitter appear at relative high temperature, along with the decreased number of Ag precipitates located in the interfacial glass-phase. Lower viscosity and higher ion diffusion velocities of interfacial glass-phase will make Ag crystallites appear at lower temperature. The increased interfacial glass layer thickness and abnormal growth of Ag crystallites, together with the decreased number of Ag precipitates cause the increase of contact resistance with the increase of sintering temperature. (C) 2016 Elsevier B.V. All rights reserved.