Indium oxide and indium-tin-oxide channel ferroelectric gate thin film transistors with yttrium doped hafnium-zirconium dioxide gate insulator prepared by chemical solution process

Abstract

Ferroelectric gate transistor (FGT) with yttrium doped hafnium-zirconium dioxide (Y-HZO) gate insulator and oxide channel with various thicknesses of In2O3 and ITO were fabricated by chemical solution deposition. First, ferroelectric properties of Y-HZO in the metal-ferroelectric-semiconductor structure with 5–22 nm thick In2O3 and 6–24 nm thick ITO, have been confirmed by polarization–voltage and capacitance–voltage (C–V) characteristics. The C–V curves showed clear butterfly loops showing the depletion of In2O3 and ITO layer. Secondly, the device performance of FGTs has been evaluated with various thicknesses of In2O3 and ITO channel layer. The fabricated FGTs exhibited typical n-channel transistor operation with a counterclockwise hysteresis loop due to the ferroelectric nature of the Y-HZO-gate insulator. It was found that FGT shows a low subthreshold voltage swing, high on/off drain current ratio of 106, large on current, and memory window.

Thermal stability of ferroelectricity in hafnium–zirconium dioxide films deposited by sputtering and chemical solution deposition for oxide-channel ferroelectric-gate transistor applications

“…26) In addition, we have demonstrated FGT using CSD ITO or CSD In 2 O 3 as a channel and CSD Y-HZO as a ferroelectric gate insulator. 27) In this work, a comparative study on stability of ferroelectricity of the sputtered HZO and vacuum annealed CSD Y-HZO films in metal-ferroelectric-semiconductor (MFS) structure has been performed. A thin ITO layer, which corresponds to the channel layer of FGT, was deposited by sputtering on sputtered HZO and CSD Y-HZO films.…”

“…Ferroelectric nature was observed with clear hysteresis and switching response for both sputtered HZO and CSD Y-HZO films, which is consistent with our previous report. [24][25][26][27][28] It is worth noting that the sputtered HZO film has superior ferroelectricity at the beginning before the re-annealing treatment. The switching current peak is more pronounced for the sputtered HZO thin film and P-E loop of CSD Y-HZO film may have some parasitic effects, although the P r value of the CSD Y-HZO looks similar to that of the sputtered film.…”

Fabrication of Ferroelectric Gate Thin‐Film Transistors with a Lanthanum‐Doped HZO Gate Insulator and Indium‐Tin‐Oxide Channel via a Solution Process

“…The FGTs consisted of MFS structures that comprised an ITO layer that was formed on the 8 at% La‐HZO specimen by using CSD; the corresponding C – V results are shown in Figure S4h, Supporting Information. [ 6 ] The specimens were annealed at 600 °C in a N 2 or O 2 atmosphere under the conditions of a flow of 1 L min −1 . Next, the Pt source/drain electrodes were deposited via sputter deposition, and they were patterned using a lift‐off process.…”

“…Ferroelectric materials are applied in many different technologies, such as nonvolatile ferroelectric random access memory, [1][2][3][4][5] ferroelectric gate transistors (FGTs), [6] negative capacitance field-effect transistors (FETs), [7,8] and ferroelectric tunnel junctions. [9] HfO 2 -based ferroelectric thin films have been garnering interest since the first report of polarization-electric field (P-E) hysteresis in 2011.…”

“…[15][16][17] They observed that, compared with undoped HZO, the La-HZO thin films have a lower leakage current and improved endurance properties; [17] thus, La-HZO is suitable for FGT applications. Previously, we reported on the fabrication of FGTs with In 2 O 3 and indium-tin-oxide (ITO) channels, and ferroelectric Y-doped HZO (Y-HZO) gate insulators; [6] the Y-HZO and ITO layers were fabricated by employing chemical solution deposition (CSD). Thus, as an extension of our previous research, in this study, we fabricated FGTs with a CSD ITO channel and a CSD La-HZO gate insulator.…”