Improvements of Electrical Characteristics in Poly-Si Nanowires Thin-Film Transistors with External Connection of a BiFeO3 Capacitor

Abstract

By a sol–gel method, a BiFeO3 (BFO) capacitor is fabricated and connected with the control thin film transistor (TFT). Compared with a control thin-film transistor, the proposed BFO TFT achieves 56% drive current enhancement and 7–28% subthreshold swing (SS) reduction. Moreover, the effect of the proposed BiFeO3 capacitor on IDS-VGS hysteresis in the BFO TFT is 0.1–0.2 V. Because dVint/dVGS > 1 is obtained at a wide range of VGS, it reveals that the incomplete dipole flipping is a major mechanism to obtain improved SS and a small hysteresis effect in the BFO TFT. Experimental results indicate that sol-gel BFO TFT is a potential candidate for digital application.

Nd dopant effect on structural properties of BiFeO3 thin films and application in a negative capacitance transistor

“…6(c), the spike behavior can be explained by the following: initial rise, initial ferroelectric response and final ferroelectric response. 21) According to Ref. 29, the negative capacitance time is defined as the elapsed time from the highest value to the lowest value of V FE in the "initial ferroelectric response," as shown in C-1 of Fig.…”

“…16) It is also revealed that incomplete dipole flipping is a major mechanism to obtain improved drain current I DS and SS in the BiFeO 3 thin-film transistor. [21][22][23] In this paper, Nd-doped BiFeO 3 (BiNdFeO 3 ) thin film on Pt is fabricated using a solgel method 24) and the poly-Si nanowire junctionless thin-film transistor externally connected to the BiNdFeO 3 capacitor is studied. In previous studies, the negative capacitance effect of the BiNdFeO 3 capacitor in a resistive-capacitive circuit is seldom discussed and is not yet used to improve the electrical properties of thin-film transistors.…”