Investigation of the Electrical Properties of Double-Gate Dual-Active-Layer Sandwich Gate Dielectrics

• Published in: Semiconductors (Woodbury, N.Y.) N.Y.), 2020-10, Vol.54 (10), p.1290
• Main Authors: Ramesh, L, Moparthi, S, Tiwari, P. K, Samoju, V. R, Saramekala, G. K
• Format: Article
• Language: English
• Subjects: Dielectrics; Electric properties; Indium; Silica; Zinc oxide
• ISSN: 1063-7826
• DOI: 10.1134/S1063782620100243

In this paper, the electrical properties of a double-gate dual-active-layer (DG-DAL) thin-film transistor (TFT) are investigated. To increase the ON-current and pixel intensity, and control the voltage stress bias, the conventional gate oxide material (silicon dioxide, SiO.sub.2) is replaced with a tri-high-k gate dielectric layer, hafnium dioxide (HfO.sub.2)/lanthanum oxide (La.sub.2O.sub.3)/hafnium dioxide (HfO.sub.2)-(HLH). Further, the performance of the proposed DG-DAL structure is compared with the single-active-layer (SAL) and dual-active-layer (DAL) TFTs. The amorphous indium-gallium zinc-oxide (a-IGZO) is considered as active layer for SAL channel region, and on the other hand, a-IGZO and indium-tin-oxide (ITO) are considered as active layers for DAL TFT and DG-DAL TFT channel regions. The parameters such as OFF-current, ON-current, I.sub.ON/I.sub.OFF ratio, threshold voltage, mobility, average subthreshold swing, etc. are evaluated for the considered structures. It is observed that the DG-DAL TFT with HLH dielectric offers high ON-current of 3.85 x 10.sup.-3 A/[mu]m, very low OFF-current of 2.53 x 10.sup.-17 A/[mu]m, very high I.sub.ON/I.sub.OFF ratio of 1.51 x 10.sup.14, threshold voltage of 0.642 V, high mobility of 35 cm.sup.2 v.sup.-1 s.sup.-1 and average subthreshold swing of 127.84 mV/dec. A commercial TCAD simulation tool ATLAS from Silvaco.sup.TM is used to investigate all the parameters for considered structures.