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Mobility-enhanced normally off hydrogen-terminated diamond FET with low interface state density using Al2O3/Nd gate stack

MetadataDetails
Publication Date2023-10-23
JournalApplied Physics Letters
AuthorsJianing Su, Wei Wang, Guoqing Shao, Genqiang Chen, Hongxing Wang
InstitutionsXi’an Jiaotong University
Citations10

A mobility-enhanced normally off hydrogen-terminated diamond (H-diamond) field-effect transistor (FET) with low interface state density has been realized using Al2O3/Nd gate stack deposited by electron beam evaporator. The threshold voltage is extracted to be āˆ’1.48 V, indicating an obvious normally off characteristic. The enhancement mode could be ascribed to the large work function difference between Nd and H-diamond. The subthreshold swing is deduced as low as 86.3 mV/dec, revealing a high working speed in the subthreshold region. More importantly, the mobility (518.5 cm2/VĀ·s) has been enhanced due to the fairly low interface state density (3.19 Ɨ 1011 cmāˆ’2Ā·eVāˆ’1). In addition, the device exhibits a relatively low trapped charge density and fixed charge density from the C-V characteristic. This work provides a simple method to realize the normally off device and suggests the great potential of adopting the Al2O3/Nd gate stack for achieving high-performance H-diamond FET.