High Performance Complementary Circuits Based on p-SnO and n-IGZO Thin-Film Transistors

Abstract

Oxide semiconductors are regarded as promising materials for large-area and/or flexible electronics. In this work, a ring oscillator based on n-type indium-gallium-zinc-oxide (IGZO) and p-type tin monoxide (SnO) is presented. The IGZO thin-film transistor (TFT) shows a linear mobility of 11.9 cm2/(V∙s) and a threshold voltage of 12.2 V. The SnO TFT exhibits a mobility of 0.51 cm2/(V∙s) and a threshold voltage of 20.1 V which is suitable for use with IGZO TFTs to form complementary circuits. At a supply voltage of 40 V, the complementary inverter shows a full output voltage swing and a gain of 24 with both TFTs having the same channel length/channel width ratio. The three-stage ring oscillator based on IGZO and SnO is able to operate at 2.63 kHz and the peak-to-peak oscillation amplitude reaches 36.1 V at a supply voltage of 40 V. The oxide-based complementary circuits, after further optimization of the operation voltage, may have wide applications in practical large-area flexible electronics.

Complementary Integrated Circuits Based on p-Type SnO and n-Type IGZO Thin-Film Transistors

“…The voltage gain at VDD = 10 V reaches as high as 112 (Fig. 2(c)), which is the highest value among complementary inverters using n-and p-type oxide TFTs below 10 V supply voltage [2,3,12,13,15,16,18,24]. The threshold voltage of the inverter, where Vin = Vout, is found to be 1.97 V and 4.25 V at VDD = 5 V and 10 V, respectively.…”

“…From the point of industrial application, high gain of complementary inverter is quite desirable in order to achieve large noise margins of the integrated circuits. However, to the best of our knowledge, the gains of the reported complementary inverters based on n-and p-type oxides are not higher than 30 under a supply voltage of 10 V until now [2,3,12,13,15,16,18,24] high-performance n-type IGZO TFTs and p-type SnO TFTs via room-temperature sputtering method which is suitable for large-scale fabrication and commercialization for transparent/flexible electronics. Moreover, we realized the integration of SnO and IGZO TFTs to achieve complementary inverters with extremely high voltage gain up to 112.…”

“…The static current will also result in a static power consumption, which may be an issue in the case of large scale integration. Complementary inverters using n-type oxide (such as In2O3, SnO2, IGZO, and ZnO) TFTs and p-type SnO TFTs have been reported [12][13][14][15][16][17][18][19]. Five-stage ring oscillators based on n-type ZnO and p-type SnO TFTs have been fabricated on glass and polyimide foil substrates [12,13].…”

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

“…It is highly desired to complement SnO with IGZO to form complementary integrated circuits as they both can be deposited using RF sputtering, which is currently used widely in the display industry. The first IGZO/SnO complementary inverter was demonstrated in 2017 with a gain of around 25 [16] , as shown in Figures 4(a) and 4(b). Then some improved IGZO/SnO inverters [10,11] , NAND [12] , NOR [13] , and XOR [13] gates were demonstrated in the following years.…”

“…Thus such device has the potential to realize a higher intrinsic voltage gain, A V , as it equals . For an IGZO SGT with an IGZO thickness of 20 nm, the average [13], [14], and [16]. Copyright © 2018,2019, IEEE.…”