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Use of high‐k encapsulation to improve mobility in trap‐limited metal‐oxide semiconductors
Author(s) -
Zeumault Andre,
Subramanian Vivek
Publication year - 2017
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201700124
Subject(s) - materials science , heterojunction , doping , optoelectronics , thin film transistor , dielectric , electron mobility , leakage (economics) , high κ dielectric , semiconductor , transistor , field effect transistor , oxide , gate dielectric , nanotechnology , electrical engineering , voltage , engineering , layer (electronics) , metallurgy , economics , macroeconomics
Low‐temperature spray‐deposited ZnO films are encapsulated by insulating Ga 2 O 3 films and the resulting electronic properties of heterostructure films and transistors are analyzed and compared to un‐encapsulated ZnO as a function of processing temperature. An enhancement in Hall mobility and field‐effect mobility is observed similar to when high‐k dielectrics are used as gate‐dielectrics in transparent conductive oxide thin‐film transistors except without the presence of undesirable device behavior such as gate‐leakage and hysteresis. Based on a recently proposed theory consisting of electron donation from high‐k dielectrics, work function measurements show that conditions for electron transfer from Ga 2 O 3 to ZnO can be met by optimally‐tuning the deposition temperature of the respective films resulting in an effective doping which is qualitatively similar to modulation doping. As a result, TFTs composed of ZnO/Ga 2 O 3 heterostructures exhibit greatly improved switching characteristics and electron transport relative to the otherwise poor performance of low‐temperature processed ZnO achieved through a simple modification to TFT device structure.