Conduction Band-offset in GeO2/Ge Stack Determined by Internal Photoemission Spectroscopy
Conduction Band-offset in GeO2/Ge Stack Determined by Internal Photoemission Spectroscopy
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DOI：
10.1149/05004.0091ecst
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发表时间：
2013-03
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通讯作者：
Wenfeng Zhang;T. Nishimura;K. Nagashio;K. Kita;A. Toriumi
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作者：
Wenfeng Zhang;T. Nishimura;K. Nagashio;K. Kita;A. Toriumi
GeO2作为钝化层由于具有良好的ge2 /Ge界面和低Dit[1]而引起了人们的持续研究兴趣。GeO2/Ge中的带线确定对于模拟输运性质至关重要，而不同基团的传导带（CB）偏移范围为0.6eV至1.8eV[2-4]。XPS通常用于测量价带（VB）偏移量，然后在带隙已知的情况下提取CB偏移量，而内部光电发射光谱（IPE）通过直接测量ge2 /Ge界面上超越势垒高度的电子来表征CB偏移量是一种更直接的方法。因此，IPE被认为可以提供更准确的CB偏移结果。本文中，我们系统地确定了在金属/GeO2/Ge MOS结构中，铝和金栅极分别用于pge衬底和nGe衬底的CB偏置。得到的CB偏置值进一步支持了GeO2作为基于ge的CMOS器件的潜在钝化层。
Introduction GeO2 attracts continuous research interests as the passivation layer owing to excellent GeO2/Ge interface with low Dit [1]. The band line-up determination in GeO2/Ge is essential for modeling the transport properties, while the reported conduction band (CB) offset by different groups ranges from 0.6eV to 1.8eV [2-4]. In comparison with XPS which is commonly used to measure the valence band (VB) offset, then to extract the CB offset when the band gap is known, the internal photoemission spectroscopy (IPE) is a more straightforward way to characterize CB offset by measuring electrons surmounting the barrier height at GeO2/Ge interface directly. Thus, the IPE is regarded to offer more accurate CB offset results. Herein, we have systematically determined the CB offset in metal/GeO2/Ge MOS structures with Al and Au gate electrodes both for pand nGe substrates. The obtained CB offset value gives further support of GeO2 as the potential passivation layer for Ge-based CMOS devices.