Microwave and furnace annealing in oxygen ambient for performance enhancement of p-Type SnO thin-film transistors

In this study, we investigated the effect of microwave-irradiation annealing (MWA) and thermal furnace annealing (FA) in oxygen ambient on the active channel layer of p-type tin-oxide (SnO) thin-film transistors (TFTs). At very low source-drain voltage of -0.1 V, the MWA at 1200 W and FA at 300 °C samples have exhibited significant improvement in the electrical characteristics such as subthreshold swing (SS) of 0.93 and 0.485 V/dec, the Ion/Ioff ratio of 1.65 x 104and 3.07 x 104, the field-effect mobility (μFE) of 0.16 and 0.26 cm2/V·s and ultra-low off-state current of 1.9 pA and 2.0 pA respectively. The observed performance enhancement was mainly attributed to the reduction of interface trap density (Nt) by tuning the power of MWA and optimizing the temperature in FA. From the result, we observed the optical band gap (Eg) increased by 6% in FA, and 12% in MWA, which confirms improved crystallinity and reduction of defect states. Additionally, a low thermal budget microwave anneal process has shown high transmittance of more than 86% in the visible region (380-700 nm). The physical characterization indicates the partial phase transformation of SnO to SnO2 with retaining p-type conductivity in both annealing process. The results demonstrate that both the annealing process could be highly promising to be used in the complementary logic circuits of new generation flexible/transparent displays.

Effects of Microwave and Furnace Annealing for P-Type SnO Thin Film Material in Oxygen Ambient

Transparent conductive oxide (TCO) semiconductors are attracted considerable attention due to a wide range of applications, such as flat panel display (FPD), touch panels, solar cells, and other optoelectronic devices. Owing to the different carrier conduction paths between n-type and P-type TCOs, the n-type TCO used in TFTs usually have high Ion/Ioff current ratio (>107) and high electron mobility (>10 cm2/V·s), P-type TCO TFTs are both lower than that of n-type one. For complementary circuits design and applications, however, both P-type and n-type semiconductor materials are equally important. For SnO thin films, it is important to adjust the ratio of Sn2+ (SnO P-type) and Sn4+ (SnO2 n-type) in order to modulate the electrical characteristics. In this investigation of post treatment for SnO thin films, both microwave annealing (MWA) and furnace annealing process with 02 ambient are studied. The results show that SnO thin films are optimized at 300 °C, 30 minutes furnace annealing, the P-type SnO/SnO2 thin film shows surface mean roughness 0.168 nm, [Sn2+]/[Sn4+] ratio as 0.838, at least 80% transmittance between 380 nm-700 nm visible light. Withthe results, SnO can be even used to fabricate high performance P-type thin film transistors (TFTs) device for future applications.

Influence of Annealing Methods on the Morphological and Optical Properties of Cu2O Nanoparticles Prepared by Chemical Bath Deposition

In this work, the cuprous oxide (Cu2O) thin film on glass substrates were fabricated at low growth temperature by a single-step aqueous solution of chemical bath deposition method. In order to optimize optical and morphology quality, the effect of two different heat treatment methods are conventional furnace annealing process and continuous wave (CW) CO2 laser annealing technique were investigated. The effect of annealing temperatures on the properties of Cu2O thin films were systematically investigated by UV-Vis spectrophotometer, X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM).

Effects of P-Type SnOx Thin-Film Transistors with N2 and O2 Ambient Furnace Annealing

Recently oxide-based thin-film transistors (TFTs) are investigated for emerging applications of the next generation display devices and other electronic circuits (Fortunato, E., et al., 2012. Oxide semiconductor thin-film transistors: A review of recent advances. Advanced Materials, 24, pp.2945–2986). Despite of the great success in n-type oxide semiconductors with high transparency and high field-effect mobility, high performance P-type oxide TFTs are so highly desired that complementary circuits can be realized with low power and high performance (Ou, W.C., et al., 2008. Anomalous P-channel amorphous oxide transistors based on tin oxide and their complementary circuits. Applied Physics Letters, 92, p.122113). There are some oxides such as SnO, CuO, Cu2O and NiO are regarded as promising P-type semiconductor materials. In this investigation, tin oxide SnOx is fabricated to be active layer for TFTs device, and furnace annealing with several combinations of nitrogen and oxygen ambient is compared to enhance the electrical characteristics of P-type SnOx TFTs (Park, K.S., et al., 2009. High performance solution-processed and lithographically patterned zinc-tin oxide thin-film transistors with good operational stability. Electrochemical and Solid-State Lett., 12, pp.H256–H258). The results show that with N2+O2 ambient, 30 minutes furnace annealing, the P-type SnOx TFTs device shows better performance with mobility (μFE) 0.883 cm2/V · S, threshold voltage (VT) −4.63 V, subthreshold swing (SS) 1.15 V/decade, and Ion/Ioff ratio 1.01×103.