One-Volt IGZO Thin-Film Transistors With Ultra-Thin, Solution-Processed Al_xO_y Gate Dielectric

Low-Voltage, Full-Swing InGaZnO-Based Inverters Enabled by Solution-Processed, Ultra-Thin AlxOy

“…The threshold voltage difference between TFT1 and TFT2 is found to be ~ 0.4 V. The linear mobility, µlin, and saturation mobility, µsat, are calculated to be 6.6 and 6.1 cm 2 /Vs for TFT1, and 5.4 and 5 cm 2 /Vs for TFT2. The electrical properties of both devices are comparable to or even better than most of the low-voltage IGZO TFTs reported previously [11,[16][17][18][19], demonstrating the potential for embedding in circuits with low-voltage operations.…”

“…However, this typically requires vacuum-based methods, such as sputtering and atomic-layer deposition (ALD), including a break of vacuum and an additional step of patterning, which are not cost-friendly and inefficient. Alternatively, one can use anodization, which is a solutionprocessed, vacuum-free method that can deposit conformal, reliable, ultra-thin oxide layers at room temperature in a very short time [11]. Recently, one-volt IGZO TFTs have been demonstrated by us using anodized, ultra-thin AlxOy as gate dielectrics [11,12].…”

“…Alternatively, one can use anodization, which is a solutionprocessed, vacuum-free method that can deposit conformal, reliable, ultra-thin oxide layers at room temperature in a very short time [11]. Recently, one-volt IGZO TFTs have been demonstrated by us using anodized, ultra-thin AlxOy as gate dielectrics [11,12]. With our anodization method, the thickness of the gate oxide layers can be easily controlled by varying the anodization voltage on the same substrate, enabling the creation of inverters based on solutionprocessing.…”

8.4: Invited Paper: Oxide devices for displays and low power electronics

“…However, one drawback of ALD is that it normally requires high vacuum and a relatively high deposition temperature. An alternative method to form ultra-thin oxides is anodization [6] . Figure 3(d) shows the schematic diagram of the anodization process for an AlO x layer.…”

“…Here, we review our recent work on a) high-performance oxidebased Schottky diodes with an ideality factor of 1.09, ultra-low noise, and operating speed >20 GHz on glass [2] and 2.45 GHz on flexible substrate [3] ; b) IGZO TFTs capable of reaching a benchmark speed of 1 GHz [4] , which are, to the best of our knowledge, the fastest oxide-based diodes and transistors to date; c) a few different methods to achieve IGZO TFTs capable of onevolt operations [5][6][7][8][9] ; d) CMOS-like oxide logic gates and functional circuits including inverters with a gain up to 150 [10,11] , NAND gate [12] , D-latch [13] , 51 stage ring oscillator [13] , complementary static random access memories [14] , and a one-bit full adder [13] , etc, by integrating SnO-based p-type TFTs with IGZO-based n-type TFTs; and finally e) novel oxide TFTs with a Schottky source contact that show no short channel effect, almost total immunity to negative bias illumination stress, and have a gain over two orders of magnitude higher than that of a typical silicon transistor [15] .…”