Variation of Oxygen Deficiency in Solution-Processed Ultra-Thin Zinc-Tin Oxide Films to Their Transistor Characteristics

Abstract

Ultra-thin zinc-tin oxide (ZTO) films (∼7 nm thick) with different Sn/(Sn+Zn) molar ratios, fabricated by using a solution process in combination of spin coating method, are applied as channel layers in thin film transistors (TFTs) with a bottom-gate top-contact structure. With regard to material characteristics, oxygen deficiency in ZTO films can be substantially decreased with the addition of different Sn contents. The non-Sn added ZnO TFT cannot be turned on whereas the Sn added ZTO channel layers perform TFT characteristics adequately, indicating the necessity of reducing oxygen deficiency by introducing Sn during the solution synthesizing process. With a Sn/(Sn+Zn) molar ratio of 0.5, the ZTO TFT exhibits the best field-effect mobility of ∼2.0 cm2/V s and a large on/off current ratio of ∼108. The electrical characteristics of ZTO TFTs are explored and correlated to the levels of oxygen deficiency associated with various Sn contents.

Printed Electronics Based on Inorganic Semiconductors: From Processes and Materials to Devices

“…Similarly, with ferroelectric gating (using a stack of (Bi,La) 4 Ti 3 O 12 (BLT) and Pb (Zr,Ti)O 3 (PZT)) field‐effect mobility of 6.5 cm 2 V −1 s −1 and a large nonvolatile memory window of output voltage of the order of several volts have been achieved . A summary of processing as well as performance parameters of various solution‐processed/printed amorphous oxides TFTs are presented in Table 4 …”

Solution processed ZnO homogeneous quasisuperlattice materials

“…32) or at temperatures as low as 250 C. 33 The demand a) Author to whom correspondence should be addressed; electronic mail: c.odwyer@ucc.ie for materials that are low cost and high performance drives research into transparent conductive oxides and amorphous oxide thin films, leading to a range of crystalline and amorphous oxides for TFTs including indium-gallium-zinc oxide (IGZO), indium zinc oxide (IZO), zinc-tin oxide, aluminum zinc oxide, hafnium-zinc-tin oxide, and others. 1,20,[34][35][36] Transparency in the visible is advantageous for some applications, particularly for "invisible electronic circuits" in future of display technology and electronics, with the proviso that lower-temperature processing and control of conduction/mobility is improved. 37 However, good control over solution-processing is paramount for high quality electronic material grade ZnO and its alloyed or doped counterparts, particularly when grown at a low temperature.…”

Control of electrical properties and gate bias stress stability in solution-processed a-IZO TFTs by Zr doping

“…The most common AOSs investigated for oxide TFTs are zinc oxide (ZnO) [9], indium zinc oxide (IZO) [5], zinc tin oxide (ZTO) [10]. There are many reports the effect of doping metal atoms in the IZO or ZTO system such as Ga [1], Ti [11], Al [12], Sr [13], Si [14], Mg [15] and Hf [16].…”