6:30 PM - 6:45 PM
▼ [21p-B203-20] Electric Field Thermopower Modulation of High-mobility InSnZnOx TFTs
Keywords:Thin Film Transistor
ITZO-TFTs (bottom-gate & top-contact type) were fabricated on ITO-coated EAGLE XG® glass substrates. Firstly, amorphous AlOx film (εr = 8, 106 nmt, Ci = 67 nF cm−2) was deposited by the ALD technique followed by the deposition of 10-nm-thick amorphous ITZO by PLD through a stencil mask. Then, the multilayer film was annealed at 350 °C in air. Finally, 20-nm-thick Ti films were evaporated as source & drain electrodes through a stencil mask.
The resultant ITZO-TFTs showed excellent transistor characteristics as shown in Fig. a (μFE ~48 cm2 V−1 s−1, μeff ~58 cm2 V−1 s−1, S.S. ~100 mV decade−1). We measured thermopower of ITZO channels with L = 800 μm and W = 400 μm when applying Vg. Figure b shows the change in the thermopower (S) with sheet carrier concentration (n2D) that obtained from Ci (Vg − Vth). The absolute value of S decreases with increasing n2D. Then, we fabricated ITZO films on EAGLE XG® and AlOx/ITO/EAGLE XG®, and measured the thermopower and bulk carrier concentration n3D (Fig. c). We extracted that the density of states effective mass of ITZO is 0.11 m0, which is lighter than that of a-IGZO (m* ~0.3 m0). Then, we compared the n2D and n3D at the same S. Interestingly, the effective thickness that is estimated as n2D/n3D is ~20 nm, which is thicker than the ITZO film thickness (~10 nm). We would like to discuss this difference in thickness at the conference.
The resultant ITZO-TFTs showed excellent transistor characteristics as shown in Fig. a (μFE ~48 cm2 V−1 s−1, μeff ~58 cm2 V−1 s−1, S.S. ~100 mV decade−1). We measured thermopower of ITZO channels with L = 800 μm and W = 400 μm when applying Vg. Figure b shows the change in the thermopower (S) with sheet carrier concentration (n2D) that obtained from Ci (Vg − Vth). The absolute value of S decreases with increasing n2D. Then, we fabricated ITZO films on EAGLE XG® and AlOx/ITO/EAGLE XG®, and measured the thermopower and bulk carrier concentration n3D (Fig. c). We extracted that the density of states effective mass of ITZO is 0.11 m0, which is lighter than that of a-IGZO (m* ~0.3 m0). Then, we compared the n2D and n3D at the same S. Interestingly, the effective thickness that is estimated as n2D/n3D is ~20 nm, which is thicker than the ITZO film thickness (~10 nm). We would like to discuss this difference in thickness at the conference.