Effects of deposition temperature on the conduction mechanisms and reliability of radio frequency sputtered TiO2 thin films

Abstract

The electrical conduction mechanisms and reliability characteristics of rf-sputtered TiO2 thin films deposited at different temperatures have been systematically investigated. Analytical results revealed that adequate sputtering temperature not only provided a superior polycrystallized TiO2 film as well as a less leakage current, but also reduced the oxygen vacancy, resulting in the Frenkel–Poole (FP) conduction mechanism of low-temperature (400–500 °C) sputtered samples transiting to the Schottky emission (SE) process of medium-temperature (600–700 °C) sputtered samples. However, for samples sputtered by higher temperature (750–800 °C), the evident oxygen deficiency due to the deteriorated crystallinity and significant Si diffusion contamination in the TiO2 films were asserted to be the two main causes leading to the SE conduction process in medium-temperature (600–700 °C) sputtered samples transiting to the FP conduction mechanism in high-temperature (750–800 °C) sputtered samples again. Besides, the excellent agreement between the E model and the time-dependent-dielectric-breakdown data suggested strongly that the exhibited best long-term reliability of metal–oxide–semiconductor capacitors with TiO2 gate oxide sputtered at 700 °C was due to the possession of superior crystallinity and less interface hole trap density at the junction of TiO2/Si, resulting in a higher thermal activation energy Ea of 0.709 eV at 5 MV/cm, reducing the breakdown occurrence.

Effect of the substrate temperature on the properties of the RF sputtered TiO2 thin films

“…RF magnetron sputtering [10][11][12] is one of the most utilized methods for obtaining uniform and dense TiO 2 thin films with well-controlled stoichiometry. In this paper, we present the influence of the growth temperature on the properties of TiO 2 thin films deposited on glass and p-Si substrates.…”

“…It is found to exhibit interesting properties (high permittivity and refractive index [1,2], good durability, biocompatibility etc. ), which makes it a promising material for gas sensors [3,4], solar cells [5,6] antireflection coatings [7], multilayer optical coatings [8], optical wave guides [9], dielectrics in memory cell capacitors [10] for static random access memory (SRAM) applications [11,12] and more recently as the body oxide of tunnel transistors or of metal oxide semiconductor transistor (MOS) [3,4,10]. As pure material, stoichiometric TiO 2 can absorb a small percentage of the sunlight.…”

The structural and electrical properties of thermally grown TiO2thin films

“…Titanium dioxide (TiO 2 ) is a popular material with many applications in electronics and optoelectronics due to its high permittivity and refractive index [1,2]. It has been investigated for static random access memory (SRAM) applications [3,4], and more recently as the body oxide of tunnel transistors [5][6][7]. Understanding the structural and electrical properties of the TiO 2 thin films is critical for the successful implementation of this material.…”

“…It has been investigated for static random access memory (SRAM) applications [3,4], and more recently as the body oxide of tunnel transistors [5][6][7]. Understanding the structural and electrical properties of the TiO 2 thin films is critical for the successful implementation of this material.…”

Study of the crystal structure, band gap and dispersion evolution in titanium oxide thin films

“…[1][2][3][4]. Many different techniques can be used for TiO 2 film fabrication, e.g., sol-gel [5], spray pyrolysis [6], chemical vapor deposition [7], sputtering [8], and evaporation [9]. The electron-beam evaporation (EBE), as one of evaporation technique, yields a high deposition rate at relatively low substrate temperatures with very high material utilization efficiency.…”