[19p-Z33-1~16] 21.1 Joint Session K "Wide bandgap oxide semiconductor materials and devices"

▼ [19p-Z33-2] Aluminum titanium oxide Thin Films Synthesized by Mist-CVD and Applied as a Gate Insulating Layer

〇(D)Arifuzzaman Rajib Rajib¹, Abdul Kuddus¹, Tomohiro Shida¹, Kojun Yokoyama¹, Keiji Ueno¹, Hajime Shirai¹ (1.Saitama Univ.)

Keywords:mist-CVD, Aluminum-Titanium oxide, MOS-FETs

Aluminum titanium oxide thin films were synthesized using mist-CVD from a composite of aluminum acetylacetonate, titanium acetylacetonate for different Al/Ti precursor mixing ratios (γ) at a furnace temperature of 550 ℃. The film deposition rate of Aluminum titanium oxide thin films decreased with an increase in the γ value due to the increased chemical stability of the Ti-solvent complex network in the solution. Further, the capacitance-voltage revealed that the dielectric constant increased from 6.23 to 18.1 with the decrease in the fixed charge density from 7.05 to 5.85x10^11 when γ value increased from 0 to 0.635. The field-effect mobility of 85 (41.4) cm^2/(V s) was obtained with a threshold voltage of 0.91 (2.1) V and an on/off ratio of 10^7 for a thickness of 39 (50)- nm- thick Aluminum titanium oxide (alumina) as a gate insulating layer, using a mechanically exfoliated ~40 -nm -thick MoSe2 flake as a channel layer. These findings imply that the mist-CVD Aluminum titanium oxide layer is a possible high-k material for the gate insulator of the MOS-FETs.