Influence of layer thickness on passivation properties in SiOx/Al2O3 stacks
Influence of layer thickness on passivation properties in SiOx/Al2O3 stacks
复制标题
层厚度对 SiOx/Al2O3 叠层钝化性能的影响
DOI：
10.1063/1.5135391
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发表时间：
2020
影响因子：
3.2
通讯作者：
J. Benick
中科院分区：
文献类型：
--
作者：
A. ek;C. Reichel;A. Richter;J. Benick
由于电荷密度可以通过SiOx层厚度来控制，因此SiOx/Al_2O_3钝化堆栈显示出有效钝化n型和p型表面的潜力。本文研究了SiOx/Al_2O_3电堆的钝化质量与SiO_x层厚度和Al_2O_3层厚度的关系。采用等离子体增强原子层沉积技术在n型和p型硅表面制备了SiOx/Al_2O_3钝化层，测量了有效表面复合速度(S E F)、界面缺陷密度(DIt)和有效固定电荷密度(Q E F)。当表面仅用Al_2O_3钝化时，钝化程度最高(n型钝化为1.1 cm/S，p型钝化为4.8 cm/S)。随着SiO_x层厚度的增加，S的Ef_f增大，达到最大值后减小。S的低Ef值与堆积或反转有关，而S Ef的最大值出现在反转的耗竭/边缘。无论是单独使用还是在SiO_x/Al_2O_3电堆中使用，增加Al_2O_3的厚度也会降低S e_f，但不影响S e_f的最大值所在位置。无论SiOx厚度如何，缺陷密度都很低(10 11 e V−1 c m−2)，n型晶片的缺陷密度总体上低于p型晶片。SiOx层降低了n型硅片的缺陷密度，并观察到DIt<；10 10e V−1 c m−2。SiO_x层厚度对有效固定电荷密度(Q，e，f，f)有很大影响，随着厚度的增加，有效固定电荷密度(Q，e，f，f)变得更正。掺杂类型对QEF有影响，n型硅比p型硅带负电荷更多。
SiOx/Al2O3 passivation stacks have shown the potential to effectively passivate both n- and p-type surfaces as the charge density may be controlled via the SiOx layer thickness. Here, the passivation quality of the SiOx/Al2O3 stacks is investigated as the function of SiOx layer thickness and Al2O3 layer thickness. The SiOx/Al2O3 passivation stacks were deposited on n- and p-type Si using plasma-enhanced atomic layer deposition and the effective surface recombination velocity ( S e f f ), interface defect density ( D i t ), and effective fixed charge density ( Q e f f ) were measured. The level of passivation was highest when the surface was passivated with only Al2O3 (1.1 cm/s and 4.8 cm/s for n-type and p-type, respectively). S e f f increased with increasing SiOx thickness, reached a maximum value, and then decreased for thicker SiOx layers. The low S e f f values correlate with accumulation or inversion while maximum S e f f appears at the depletion/edge of inversion. Increasing the Al2O3 thickness also lowered S e f f, both when used on its own and in SiOx/Al2O3 stacks but did not affect where the maximum S e f f was located. The defect density was low ( D i t < 10 11 e V − 1 c m − 2 ) irrespective of SiOx thickness and the n-type wafers showed an overall lower defect density than p-type wafers. The SiOx layer lowered the defect density for n-type wafers and D i t < 10 10 e V − 1 c m − 2 could be observed. The SiOx layer thickness greatly affected the effective fixed charge density ( Q e f f ) which became more positive as the thickness increased. The doping type had an influence on the resulting Q e f f with the n-type Si becoming more negatively charged than p-type.