High-Performance Top-Gate Thin-Film Transistor with an Ultra-Thin Channel Layer

Abstract

Metal-oxide thin-film transistors (TFTs) have been implanted for a display panel, but further mobility improvement is required for future applications. In this study, excellent performance was observed for top-gate coplanar binary SnO2 TFTs, with a high field-effect mobility (μFE) of 136 cm2/Vs, a large on-current/off-current (ION/IOFF) of 1.5 × 108, and steep subthreshold slopes of 108 mV/dec. Here, μFE represents the maximum among the top-gate TFTs made on an amorphous SiO2 substrate, with a maximum process temperature of ≤ 400 °C. In contrast to a bottom-gate device, a top-gate device is the standard structure for monolithic integrated circuits (ICs). Such a superb device integrity was achieved by using an ultra-thin SnO2 channel layer of 4.5 nm and an HfO2 gate dielectric with a 3 nm SiO2 interfacial layer between the SnO2 and HfO2. The inserted SiO2 layer is crucial for decreasing the charged defect scattering in the HfO2 and HfO2/SnO2 interfaces to increase the mobility. Such high μFE, large ION, and low IOFF top-gate SnO2 devices with a coplanar structure are important for display, dynamic random-access memory, and monolithic three-dimensional ICs.

Remarkably High-Performance Nanosheet GeSn Thin-Film Transistor

“…In addition, the non-negligible I DS at V GS = 0 V will lead to high standby power. [17,20,[43][44][45]. In this study, a high-κ gate dielectric was used to increase the gate capacitance and I ON , which is widely used for Si metal-oxide-semiconductor (MOS) FET and TFT devices.…”

“…To realize system-on-panel (SoP) and monolithic three-dimensional (3D) integrated circuits (ICs) [8][9][10][11], high-performance n-type and p-type TFT devices (nTFT and pTFT, respectively) are required to form low-DC-power complementary TFTs (CTFTs) [12][13][14][15]. For oxide nTFTs, excellent device performance with a high field-effect mobility (µ FE ), of ~100 cm 2 /V•s; a sharp turn-on subthreshold swing (SS), of ~100 mV/dec; and a large on-current/off-current (I ON /I OFF ) ratio, of >10 6 , has been achieved using a SnO 2 channel material [16][17][18][19][20]. However, because of the fundamental physical restrictions [30,31], the mobility of oxide pTFTs is generally less than 10 cm 2 /V•s [22][23][24][25], which remains a basic challenge for CTFTs.…”

Exceedingly High Performance Top-Gate P-Type SnO Thin Film Transistor with a Nanometer Scale Channel Layer

“…To inspect the stability of the top-gate SnO TFT devices, the devices were measured at as-fabricated and after retention in air ambient for two months, as depicted in Figure 8. In comparison with the conventional bottom-gate structure, such top-gate device shows huge stability improvement after retention in air [32], which is due to fully covered channel layer by metal-gate and gate-dielectric. Therefore, both the 100 and 200 • C annealed top-gate transistors show only slight degradation after exposure in air for two months.…”

Oxygen Concentration Effect on Conductive Bridge Random Access Memory of InWZnO Thin Film

“…Therefore, a defect-rich switching layer (upper layer) may be good for keeping Cu ions during the set process (1). However, the enhanced conductive filament near the Pt electrode might also be difficult to be ruptured by the Joule heating effect during the reset process (3). Therefore, a less defective IWZOy switching layer (bottom layer) may introduce a thinner conductive filament that would be easier to be ruptured.…”

“…In recent years, transparent amorphous oxide semiconductors (TAOSs) have attracted much attention in the novel application of electronic devices [ 1 , 2 ] such as thin film transistors [ 3 , 4 ], sensors [ 5 ], and memory [ 6 , 7 , 8 ]. From many options of TAOSs materials, InGaZnO is the most widely studied because of high mobility, excellent reliability and good uniformity.…”