P‐194: Late‐News Poster: Self‐Aligned Double‐Gate Cu‐MIC Poly‐Ge 1‐x Sn x Thin‐Film Transistors on a Glass Substrate

Polycrystalline germanium-tin (Ge 1−x Sn x ) thin films with a thickness of 15 nm were grown at 500 °C using Cu-induced crystallization. The films were applied to fabricate four-terminal (4T) thin-film transistors (TFTs) on a glass substrate. The top gate (TG) was fabricated from 30 nm thick SiO 2 , while the bottom gate (BG) consisted of a double layer of HfO 2 and SiO 2 with a capacitance equivalent thickness of 16 nm. Aluminuminduced lateral metallization of the source and drain (SD) was implemented to decrease the parasitic resistance of the SD. The I on /I off of the double gate approximately corresponded to 1 × 10 4 . Furthermore, 4T poly-Ge 1−x Sn x TFTs operated with a field-effect mobility of 20 cm 2 V −1 s −1 for the TG drive and 12 cm 2 V −1 s −1 for the BG drive at a control gate voltage of 0 V in both cases. A p-channel enhancement/depletion inverter was validated based on the precise control of threshold voltage using a control gate.

Section: Introductionmentioning

confidence: 99%

Four-terminal polycrystalline Ge_1−xSn _x thin-film transistors using copper-induced crystallization on glass substrates and their application to enhancement/depletion inverters

Miyazaki¹,

Hara²

2020

“…The TFTs had an on/off ratio of 2 × 10 3 and a mobility of 19 cm 2 V −1 s −1 under simultaneous operation of TG and BG. These techniques have been adapted to form four-terminal (4T) poly-Ge TFTs, DG poly-Ge x Sn 1-x TFTs, and 4T poly-Ge x Sn 1-x TFTs on glass substrates [30][31][32][33] in which metal-induced crystallization (MIC) using copper (Cu), [34][35][36][37][38][39] instead of standard SPC, was employed to grow high-quality, thin poly-Ge film at a low temperature. These TFTs are also applicable to flexible electronics because of their low crystallization temperature of Cu-MIC.…”

Section: Introductionmentioning

confidence: 99%

Double-gate polycrystalline-germanium thin-film transistors using copper-induced crystallization on flexible plastic substrate

Utsumi¹,

Nishiguchi²,

Miyazaki³

et al. 2019

Self Cite

In this study, planar metal double-gate (DG) p-channel (p-ch) junctionless polycrystalline germanium thin-film transistors (TFTs) were fabricated on a spin-coated polyimide (PI) substrate via metal-induced crystallization (MIC) using copper (Cu) and an aluminum-induced lateral metallization source-drain. The maximum nominal mobility, which was calculated from transconductance under the simultaneous operation of the top and bottom gates, was 32 cm 2 V −1 s −1 , and an on/off ratio of 2 × 10 3 was achieved owing to the Cu-MIC poly-Ge film, low parasitic resistance of the source-drain, and the fully depleted channel. Moreover, the performance of the DG Cu-MIC poly-Ge TFT did not drastically degrade once the PI had been peeled off the glass substrate. The proposed poly-Ge TFT can be used to fabricate p-ch TFTs on plastic substrates.

“…Details regarding the preparation procedures for thin films can be found in other studies. 11,21) In summary, the substrates used were fused quartz glass. The amorphous layers, which have three structure types, were deposited by radio frequency (rf) sputtering without heating the substrate.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Several TEM images and SIMS profiles have been demonstrated in other studies. 11,21,[24][25][26] 3. Results and discussion 3.1.…”

Section: Experimental Methodsmentioning

confidence: 99%

Raman scattering spectroscopy for solid-phase and metal-induced crystallization of extremely thin germanium films on glass

Kitahara¹,

Tsukada²,

Kanagawa³

et al. 2021

Self Cite

Raman scattering spectroscopy was applied to characterize polycrystalline germanium (Ge) on noncrystalline substrates fabricated by solid-phase crystallization and metal-induced crystallization (MIC) using copper (Cu) and tin (Sn) as the catalyzer. The subject was focused on the material for thin-film transistors in which the precursors, with the thickness of only 15 nm, were deposited by sputtering. The optical phonon mode exhibited considerable asymmetry and was separated into the following three components: crystal, low-dimensional nanosized crystallite (NC), and amorphous. The width and frequency shift of the crystal component were analyzed using the phonon confinement effect, thermal stress, and Sn composition. The transition from amorphous to the NC state was associated with the disorder in the precursor. The addition of a restrained amount of Cu led to the evident progress of crystallization and simultaneous suppression of the NC transition. The Sn composition of 3 at% was insufficient to exhibit a noticeable MIC effect.