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Investigation of the Determining Factors for the “Mobility Boost” in High‐ k ‐Gated Transparent Oxide Semiconductor Thin‐Film Transistors
Author(s) -
Sun Yuhang,
Kim Junkyu,
Chatterjee Neel,
Swisher Sarah L.
Publication year - 2021
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.202001037
Subject(s) - materials science , thin film transistor , high κ dielectric , optoelectronics , gate dielectric , electron mobility , capacitance , dielectric , transistor , semiconductor , gate oxide , oxide , nanotechnology , layer (electronics) , electrical engineering , voltage , electrode , chemistry , engineering , metallurgy
In metal‐oxide thin‐film transistors (TFTs), high‐ k gate dielectrics often yield a higher electron mobility than SiO 2 . However, investigations regarding the mechanism of this high‐ k “mobility boost” are relatively scarce. To explore this phenomenon, solution‐processed In 2 O 3 TFTs are fabricated using eight different gate dielectrics (SiO 2 , Al 2 O 3 , ZrO 2 , HfO 2 , and bilayer SiO 2 /high‐ k structures). With these structures, the total gate capacitance can be varied independently from the semiconductor–dielectric interface to study this mobility enhancement. It is shown that the mobility enhancement is a combination of the effects of areal gate capacitance and interface quality for disordered oxide semiconductor devices. The ZrO 2 ‐gated TFTs achieve the highest mobility by inducing more accumulation charge with higher gate capacitance. Surprisingly, however, when the gate capacitance is held constant, no mobility enhancement is observed with the high‐ k gate dielectrics compared to SiO 2 .