Ultrathin tin sulfide field-effect transistors with subthreshold slope below 60 mV/decade

Mircea Dragoman; Adrian Dinescu; Andrei Avram; Daniela Dragoman; Silviu Vulpe; Martino Aldrigo; Tudor Braniste; Victor Suman; Emil Rusu; Ion Tiginyanu

doi:10.1088/1361-6528/ac7cf8

Ultrathin tin sulfide field-effect transistors with subthreshold slope below 60 mV/decade

Nanotechnology. 2022 Jul 15;33(40). doi: 10.1088/1361-6528/ac7cf8.

Authors

Mircea Dragoman¹, Adrian Dinescu¹, Andrei Avram¹, Daniela Dragoman^{2

3}, Silviu Vulpe¹, Martino Aldrigo¹, Tudor Braniste⁴, Victor Suman⁵, Emil Rusu⁵, Ion Tiginyanu^{4

6}

Affiliations

¹ National Institute for Research and Development in Microtechnologies, 126A Erou Iancu Nicolae Street, 077190 Voluntari (Ilfov), Romania.
² Univ. of Bucharest, Physics Faculty, PO Box MG-11, 077125 Bucharest, Romania.
³ Academy of Romanian Scientists, Str. Ilfov 3, 050044 Bucharest, Romania.
⁴ National Center for Materials Study and Testing, Technical University of Moldova, 168 Stefan cel Mare Av., 2004 Chisinau, Moldova.
⁵ Institute of Electronic Engineering and Nanotechnologies, Academiei Street 3/3, 2028 Chisinau, Moldova.
⁶ Academy of Sciences of Moldova, 1 Stefan cel Mare Av., 2004 Chisinau, Moldova.

PMID: 35767973
DOI: 10.1088/1361-6528/ac7cf8

Abstract

In this paper, we present for the first time a field-effect-transistor (FET) having a 10 nm thick tin sulfide (SnS) channel fabricated at the wafer scale with high reproducibility. SnS-based FETs are in on-state for increasing positive back-gate voltages up to 6 V, whereas the off-state is attained for negative back-gate voltages not exceeding -6 V, the on/off ratio being in the range 10²-10³depending on FET dimensions. The SnS FETs show a subthreshold slope (SS) below 60 mV/decade thanks to the in-plane ferroelectricity of SnS and attaining a minimum value SS = 21 mV/decade. Moreover, the low SS values can be explained by the existence of a negative value of the capacitance of the SnS thin film up to 10 GHz (for any DC bias voltage between 1 and 5 V), with the minimum value being -12.87 pF at 0.1 GHz.

Keywords: 2D materials ferroelectricity; RF magnetron sputtering; ferroelectrics; microwaves; semiconductors; thin films; tin sulfide.

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