The Sintering Trajectory and Electrical Properties of Niobium‐Doped Titania Sputtering Targets

Abstract

Nb-doped TiO 2 (TNO) films, which are highly conductive and transparent, can be used as transparent conductive oxide (TCO) films. A predominant manufacturing method for TCO film is magnetron sputtering, and the material of the sputtering target affects the performance of the film. The objective of this study was to investigate the sintering densification, microstructure, and electrical properties of TNO and TiO 2 sputtering targets. The results showed that the segregation of Nb at the grain boundary in TNO helps to facilitate densification and inhibit grain growth. After 1200°C sintering, the sintered density of TNO target achieves almost 100% of the theoretical density. Moreover, the Nb 2 O 5 additive greatly improves the electrical properties, decreasing the resistivity of TiO 2 from >10 8 Ωcm to 4.6 3 10 1 Ωcm. Correlations between TNO sputtering target investigated in this study and TNO sputtered film reported in the literature are also preliminarily established. The resistivity of TNO film with an anatase structure is obviously lower than that of TNO target with a rutile structure. M.P. Paranthaman-contributing editor Manuscript No. 35178.

Preparation and sintering of indium–gallium–zinc oxide ceramics with different zinc oxide contents

“…Given the importance of sputtering targets, the processes and properties of sputtering targets for TCO films have been extensively investigated, particularly those of AZO and gallium-doped zinc oxide (GZO) [20,21,[25][26][27][28][29][30][31][32][33][34][35][36][37]. Unfortunately, the process and characteristics of IGZO targets have been studied relatively little [3,4].…”

Improving the electrical properties of niobium-doped titania sputtering targets by sintering in oxygen-deficient atmospheres

“…3. Moreover, in a previous study, energy dispersive X-ray analyses showed that the Nb contents inside the grain and at the grain boundary were 1.2 at% and 3.5 at%, respectively [15]. The segregation of Nb at the grain boundary can change the grain boundary energy, inhibit the grain growth, and facilitate the densification of TiO 2 ceramic [15].…”

“…The amounts of the dispersant and the binder were weighted according to the weight of the dry powder. The detailed procedures of slurry preparation were described in a previous study [15]. The as-prepared slurries were spray-dried with a spray dryer (L-8, Ohkawara Kakohki Co., Yokohama, Japan).…”

“…Unfortunately, the process and the characteristics of the TNO target were not reported in that study [4]. Wu and Chen [15] recently investigated the sintering behaviors and electrical properties of TiO 2 and TNO (97 mol% TiO 2 : 3 mol% Nb 2 O 5 ) ceramic targets sintered in air. They found that 3 mol% Nb 2 O 5 dopant greatly decreases the resistivity of a TiO 2 target from 410 8 Ω cm to 4.6 Â 10 1 Ω cm.…”