Low-Temperature Plasma-Enhanced Atomic Layer Deposition of Tin(IV) Oxide from a Functionalized Alkyl Precursor: Fabrication and Evaluation of SnO₂-Based Thin-Film Transistor Devices

Abstract

A bottom-up process from precursor development for tin to plasma-enhanced atomic layer deposition (PEALD) for tin­(IV) oxide and its successful implementation in a working thin-film transistor device is reported. PEALD of tin­(IV) oxide thin films at low temperatures down to 60 °C employing tetrakis-(dimethylamino)­propyl tin­(IV) [Sn(DMP)4] and oxygen plasma is demonstrated. The liquid precursor has been synthesized and thoroughly characterized with thermogravimetric analyses, revealing sufficient volatility and long-term thermal stability. [Sn­(DMP)4] demonstrates typical saturation behavior and constant growth rates of 0.27 or 0.42 Å cycle–1 at 150 and 60 °C, respectively, in PEALD experiments. Within the ALD regime, the films are smooth, uniform, and of high purity. On the basis of these promising features, the PEALD process was optimized wherein a 6 nm thick tin oxide channel material layer deposited at 60 °C was applied in bottom-contact bottom-gate thin-film transistors, showing a remarkable on/off ratio of 107 and field-effect mobility of μFE ≈ 12 cm2 V–1 s–1 for the as-deposited thin films deposited at such low temperatures.

From Precursor Chemistry to Gas Sensors: Plasma‐Enhanced Atomic Layer Deposition Process Engineering for Zinc Oxide Layers from a Nonpyrophoric Zinc Precursor for Gas Barrier and Sensor Applications

“…[ 51 ] A solution of ZnCl 2 (3.47 g, 25,5 mmol) in 50 mL THF was cooled to 0 °C and added dropwise to a cooled (0 °C) solution of 3‐( N , N ‐dimethylamino)propyl magnesium chloride (51 mmol, 0.911 mol L −1 ) in THF that was synthesized as described in literature. [ 69 ] The resulting suspension was allowed to warm up and was refluxed over night at 80 °C and afterwards it was stirred at room temperature. The THF was removed under reduced pressure and the colorless solid was extracted in 120 mL pentane.…”

Recent progress and perspectives on atomic‐layer‐deposited semiconducting oxides for transistor applications

“…However, the high N e (≥10 18 cm −3 ) in SnO 2 due to facile formation of V O frequently causes a weak drain current modulation capability in the resulting TFTs. Most studies of ALD‐derived SnO 2 TFTs have focused on effective suppression of the high N e 52–54 . Mai et al 53 investigated the electrical characteristics of TFTs with different SnO 2 channel thicknesses at 60°C using Sn (DMP) 4 and O 2 plasma as a precursor and reactant, respectively.…”

“…Most studies of ALD‐derived SnO 2 TFTs have focused on effective suppression of the high N e 52–54 . Mai et al 53 investigated the electrical characteristics of TFTs with different SnO 2 channel thicknesses at 60°C using Sn (DMP) 4 and O 2 plasma as a precursor and reactant, respectively. Improvement in the switching capability of TFTs was observed by decreasing the channel thickness of the SnO 2 .…”

“…(A) Representative transfer characteristics of SnO 2 TFTs with different thicknesses of SnO 2 grown at 60°C and (B) their corresponding μ FE and V TH values. Reprinted with permission 53 . Copyright 2019, American Chemical Society.…”

Adsorptive and photocatalytic removal of carcinogenic methylene blue dye by SnO2 nanorods: an equilibrium, kinetic and thermodynamics exploration

“…The SnO 2 nanoparticles are a semiconductor of the n-type with a 3.6 eV bandgap that makes them a flexible metal oxide [6]. In the area of the catalyst [7], solar cell [8], transistor [9], gas sensing [10] and photovoltaic energy conversion [11], the SnO 2 has been used extensively.…”