Investigation of the Mechanism for Ohmic Contact Formation in Ti/Al/Ni/Au Contacts to β-Ga2O3 Nanobelt Field-Effect Transistors
Investigation of the Mechanism for Ohmic Contact Formation in Ti/Al/Ni/Au Contacts to β-Ga2O3 Nanobelt Field-Effect Transistors
复制标题
β-Ga2O3 纳米带场效应晶体管 Ti/Al/Ni/Au 接触中欧姆接触形成机制的研究
DOI：
10.1021/acsami.9b09166
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发表时间：
2019-09-04
影响因子：
9.5
通讯作者：
Zhang, David Wei
中科院分区：
文献类型：
--
作者：
Chen, Jin-Xin;Li, Xiao-Xi;Zhang, David Wei
电极和沟道层之间的接触问题对于宽带隙半导体至关重要，特别是β-Ga 2 O3，因为其具有超大的带隙（4.6-4.9 eV）。它对器件性能影响很大，因此需要特别注意。本工作制备了高性能的β-Ga_2 O_3纳米带场效应晶体管，该晶体管在多层金属叠层Ti/Al/Ni/Au（30/120/50/50 nm）和非故意掺杂的β-Ga_2 O_3沟道衬底之间具有欧姆接触。利用X射线光电子能谱（XPS）研究了不同退火温度下β-Ga_2 O_3欧姆接触的形成机理。结果表明，在快速热退火过程中β-Ga_2 O_3/金属间化合物界面处形成的氧空位是形成低电阻欧姆接触的主要原因。退火后，电极和非故意掺杂的β-Ga 2 O 3之间的接触电阻（R-c）降低到近似9.3 Ω mm。这项工作指出了接触工程对未来改进β-Ga 2 O 3器件性能的重要性，并为β-Ga 2 O 3在电子学和光电子学中的更广泛应用奠定了坚实的基础。
The issue of contacts between the electrode and channel layer is crucial for wide-bandgap semiconductors, especially the beta-Ga2O3 due to its ultra-large bandgap (4.6-4.9 eV). It affects the device performance greatly and thus needs special attention. In this work, the high-performance beta-Ga2O3 nanobelt field-effect transistors with Ohmic contact between multilayer metal stack Ti/Al/Ni/Au (30/120/50/50 nm) and unintentionally doped beta-Ga2O3 channel substrate have been fabricated. The formation mechanism of Ohmic contacts to beta-Ga2O3 under different annealing temperatures in an N-2 ambient is systematically investigated by X-ray photoelectron spectroscopy. It is revealed that the oxygen vacancies at the interface of beta-Ga2O3/intermetallic compounds formed during rapid thermal annealing are believed to induce the good Ohmic contacts with low resistance. The contact resistance (R-c) between electrodes and unintentionally doped beta-Ga2O3 reduces to, similar to 9.3 Omega mm after annealing. This work points to the importance of contact engineering for future improved beta-Ga2O3 device performance and lays a solid foundation for the wider application of beta-Ga2O3 in electronics and optoelectronics.