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Small Subthreshold Swing Diamond Field Effect Transistors With SnO2 Gate Dielectric

MetadataDetails
Publication Date2022-06-23
JournalIEEE Transactions on Electron Devices
AuthorsShi He, Wei Wang, Genqiang Chen, Shumiao Zhang, Qi Li
InstitutionsXi’an Jiaotong University
Citations14

A small subthreshold swing (SS) hydrogen-terminated diamond field-effect transistor is realized by using a wide bandgap material (SnO <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sub> ). Results showed an SS of 106.4 mV/dec, which should be ascribed to the low interface state density (1.05 <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>$\times10$ </tex-math></inline-formula> <sup xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;12&lt;/sup> cm <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>$^{-2}\cdot $ </tex-math></inline-formula> eV <sup xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;−1&lt;/sup> ) between SnO <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sub> and diamond. The fixed charge density and trapped charge density are <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>$1.1\times10$ </tex-math></inline-formula> <sup xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;12&lt;/sup> cm <sup xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;−2&lt;/sup> and <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>$8.6\times10$ </tex-math></inline-formula> <sup xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;11&lt;/sup> cm <sup xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;−2&lt;/sup> , respectively. Leakage current between source and gate is less than <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>$2.1\times10$ </tex-math></inline-formula> <sup xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;−8&lt;/sup> A at gate voltages from −5.0 to 1.0 V and the breakdown voltage is measured to be −180 V. In addition, the devices exhibit normally- OFF characteristics, whose threshold voltage and maximum drain current density are −0.12 V and −21.6 mA/mm with 4- <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>$\mu \text{m}$ </tex-math></inline-formula> gate at <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>${V}_{GS} = -3$ </tex-math></inline-formula> V. The ON/OFF ratio is around 10 <sup xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;7&lt;/sup> and the maximum effective mobility is extracted to be 165 cm <sup xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sup> /(Vs). This work indicates that SnO <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sub> dielectric could form low interface state density with hydrogen-terminated diamond surface and it also provides a simple method to realize normally- OFF devices.