Corrugated Heterojunction Metal‐Oxide Thin‐Film Transistors with High Electron Mobility via Vertical Interface Manipulation

Abstract

A new strategy is reported to achieve high-mobility, low-off-current, and operationally stable solution-processable metal-oxide thin-film transistors (TFTs) using a corrugated heterojunction channel structure. The corrugated heterojunction channel, having alternating thin-indium-tin-zinc-oxide (ITZO)/indium-gallium-zinc-oxide (IGZO) and thick-ITZO/IGZO film regions, enables the accumulated electron concentration to be tuned in the TFT off- and on-states via charge modulation at the vertical regions of the heterojunction. The ITZO/IGZO TFTs with optimized corrugated structure exhibit a maximum field-effect mobility >50 cm V s with an on/off current ratio of >10 and good operational stability (threshold voltage shift <1 V for a positive-gate-bias stress of 10 ks, without passivation). To exploit the underlying conduction mechanism of the corrugated heterojunction TFTs, a physical model is implemented by using a variety of chemical, structural, and electrical characterization tools and Technology Computer-Aided Design simulations. The physical model reveals that efficient charge manipulation is possible via the corrugated structure, by inducing an extremely high carrier concentration at the nanoscale vertical channel regions, enabling low off-currents and high on-currents depending on the applied gate bias.

Recent Advances of Solution-Processed Heterojunction Oxide Thin-Film Transistors

“…As a product of structural engineering technology, heterojunction oxide TFTs can take advantage of the excellent electrical properties of each layer [30,37]. As the front-channel layer has good conductivity, it can provide higher carrier concentration, thus forming maximum charge accumulation and finally achieving high mobility [10,41,42].…”

“…Through careful interface engineering, electron transfer and confinement at the heterointerface can occur because of a large conduction band offset between the two layers, resulting in the formation of 2D electron gas in the interface [55]. The formation of 2D electron gas enables the realization of TFTs with mobilities close to the theoretical limit set by phonon scattering in the absence of impurity scattering [30]. In this situation, the mobility of the heterojunction device is often several times or even ten times higher than that of the single-layer device.…”

Analisis Molekular dan Transpor Ion Amonium Clorida

“…Dimana :u = koefisien perbandingan, dan disebut juga dengan mobilitas ion (139,140) Perhitungan kecepatan hanyut : Pemisalan Jika potensial NH4Cl 4,5 V dan jarak antara elektroda adalah 1,5 cm, maka kecepatan hanyutnya dapat dihitung sebagai berikut :…”

The Role of Dual-Stacked Oxide Semiconductor in High Performance Thin Film Transistors

“…Although there have been many studies such as various types of doping [14][15][16][17] , material changes [18][19][20][21][22][23][24][25] , and OS lms reinforcement [26][27][28][29] , there have been limitation to a single OS-based TFT due to low eld-effect mobility. To address this issue, dual-stacked OS-based TFTs have been recently considered potential candidates to improve eld-effect mobility, and researches showing a relatively high eld-effect mobility (30~50 cm 2 /V•s) have been reported [30][31][32][33][34][35] . However, they still have a considerably low on-off current ratio (<10 6 ), an undesirable threshold voltage far from 0 V, or an unstable reliability caused by bias stress.…”