超薄SiO_x钝化层所导致的半导体-绝缘体-半导体异质结高频隧道电容溢出现象

发布时间：2018-06-03 18:21

本文选题：超薄钝化层 + 隧道CV　；参考：《科学通报》2017年Z2期

【摘要】：从高频电容电压特性测试中发现的隧道电容溢出现象出发,研究了具有超薄钝化层的半导体-绝缘体-半导体(semiconductor-insulator-semiconductor SIS)异质结器件界面处独特的电荷存储特性.从SIS 1 MHz频率下的CV特性可知,当外加偏压小于V_T(voltage tunneling)时,SIS界面处于耗尽状态,而当外加栅压超过V_T之后,SIS的高频电容将远超仪器量程趋于无穷大,可概括称为隧道电容溢出现象.从SIS的XPS(X-ray photoemission spectroscopy)深度剖析结果可知,具有不同厚度的ITO(indium tin oxide)的SIS器件界面钝化层所含元素组分并无差别.但从TEM(transparent electron microscope)的结果来看,钝化层厚度随ITO的增加而增加,分析表明不同ITO厚度的SIS所对应V_T值不同的主要原因是由于钝化层厚度的不同.通过对实验结果的分析,本文给出了隧道电容溢出现象的载流子输运的能带模型.结果表明,隧道电容溢出是由于超薄钝化层无法使大量电子在界面处积累所致.且同一器件隧道电容溢出现象是可重复的,不会对器件带来物理损伤,这是采用直接磁控溅射工艺制备SIS异质结太阳电池稳定性的体现.
[Abstract]:Based on the tunneling capacitance overflow phenomenon found in the measurement of the voltage characteristics of high frequency capacitors, the unique charge storage characteristics at the interface of semiconductor insulator-semiconductor SISs with ultra-thin passivating layer are studied. According to the CV characteristics of SIS 1 MHz frequency, when the applied bias voltage is less than that of V_T(voltage tunneling, the interface is in a depleted state, and when the external gate voltage exceeds it, the high frequency capacitance of the MHz will tend to infinity. Can be summarized as tunnel capacitance overflow phenomenon. The results of XPS(X-ray photoemission specular analysis of SIS show that there is no difference in elements in the interface passivation layer of SIS devices with different thickness of ITO(indium tin oxide. However, from the results of TEM(transparent electron microscopes, the thickness of passivated layer increases with the increase of ITO. The analysis shows that the main reason for the difference of the T value of SIS with different ITO thickness is due to the difference of the thickness of the passivated layer. Based on the analysis of the experimental results, the energy band model of the carrier transport of the tunneling capacitance overflow phenomenon is presented in this paper. The results show that the tunnel capacitance overflow is due to the inability of the thin passivation layer to accumulate a large number of electrons at the interface. The phenomenon of tunneling capacitance overflow of the same device is repeatable and will not cause physical damage to the device. This is the embodiment of the stability of SIS heterojunction solar cells fabricated by direct magnetron sputtering.
【作者单位】：上海大学物理系索朗光伏材料与器件R&D联合实验室;上海大学分析测试与结构研究中心;
【基金】：国家自然科学基金(61274067,60876045) SHU-SOEN’s PV联合实验室基金(SS-E0700601)资助
【分类号】：TN303

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