Sputtered Modified Barium Titanate for Thin-Film Capacitor Applications

Abstract

New apparatus and a new process for the sputter deposition of modified barium titanate thin-films were developed. Films were deposited at temperatures up to 900 °C from a Ba0.96Ca0.04Ti0.82Zr0.18O3 (BCZTO) target directly onto Si, Ni and Pt surfaces and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Film texture and crystallinity were found to depend on both deposition temperature and substrate: above 600 °C, the as-deposited films consisted of well-facetted crystallites with the cubic perovskite structure. A strongly textured Pt (111) underlayer enhanced the (001) orientation of BCZTO films deposited at 900 °C, 10 mtorr pressure and 10% oxygen in argon. Similar films deposited onto a Pt (111) textured film at 700 °C and directly onto (100) Si wafers showed relatively larger (011) and diminished intensity (00ℓ) diffraction peaks. Sputter ambients containing oxygen caused the Ni underlayers to oxidize even at 700 °C: Raising the process temperature produced more diffraction peaks of NiO with increased intensities. Thin-film capacitors were fabricated using ~500 nm thick BCZTO dielectrics and both Pt and Ni top and bottom electrodes. Small signal capacitance measurements were carried out to determine capacitance and parallel resistance at low frequencies and from these data, the relative permittivity (εr) and resistivity (ρ) of the dielectric films were calculated; values ranged from ~50 to >2,000, and from ~104 to ~1010 Ω∙cm, respectively.

Ultraviolet radiation detection by barium titanate thin films grown by sol–gel hydrothermal method

“…[13,[15][16][17][18]. Amongst them, Sol-gel-hydrothermal (SG-HT) technique is a promising chemical method for low cost, low temperature fabrication of BTO thin films with large surface area and hence may be useful for sensing applications [11]. Although, there are few reports on the fabrication of BTO thin film using sol-gel hydrothermal method, but have not been explored for the sensing applications [18,19].…”

“…In the last two decades, there has been increasing demand for reliable photodetectors for detection of UV radiation due to its harmful effects [10]. The development of UV photodetectors is important because of its potential applications in the various fields of science and technology, including space science, aircraft science, defense and other industries [11]. Lead zirconate titanate (PZT) having very high piezoelectric coefficient has been widely used for the realization of UV photodetectors [2,3].…”

NOx Sensing Properties of Barium Titanate Thin Films

“…Barium Titanate, BaTiO 3 (BTO) thin film is the most attractive ferroelectric material with high dielectric constant and is used for various applications including UV sensing, capacitors, memories etc. [4][5][6]. So far only ferroelectric and electrical properties of BTO have been widely studied and very few reports available on its gas sensing properties.…”

Comprehensive examination of dopants and defects in BaTiO3from first principles

“…In fact, the chemical doping of ABO 3 compounds is essential in many applications, e.g., to tune the band gap of the host material, 7 to enhance or suppress oxygen ion formation and conductivity, 8,9 to manipulate and control the electrical and electroactive behavior, 10,11 to tune physical properties such as the Curie temperature and domain switching, 12,13 and more recently, to optimize the electrochemical or catalytic activity of the host material. 14,15 Within the class of ABO 3 perovskite-type materials, BaTiO 3 (BTO) is perhaps the most widely used [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] and studied 6,[24][25][26] multifunctional ceramic material. The extensive body of past experimental [27][28][29][30][31][32][33] and theoretical [34][35][36] studies of dopants in BTO has lead to enormous insights, which continue to grow.…”