Open AccessEffect of atomic layer deposited ultra‐thin SiO 2 layer on vapour‐liquid‐solid (VLS) grown high dielectric TiO 2 film for Si‐based MOS device applications
Author(s) -
Lodh Soham,
Chakraborty Rajib,
Das Anindita
Publication year - 2021
Publication title -
micro and nano letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.25
H-Index - 31
ISSN - 1750-0443
DOI - 10.1049/mna2.12011
Subject(s) - passivation , materials science , dielectric , thin film , optoelectronics , quantum tunnelling , substrate (aquarium) , layer (electronics) , epitaxy , analytical chemistry (journal) , atomic layer deposition , nanotechnology , chemistry , oceanography , chromatography , geology
Abstract Titanium dioxide (TiO 2 ) ultra‐thin films (≈13 nm) are grown on p‐type Si substrate <400> with and without atomic layer deposited SiO 2 (5 nm) passivation layer by employing vapour‐liquid‐solid technique. Scanning electron microscope images reveal high quality film for both the samples. The formation of a crystalline TiO 2 film is confirmed by X‐ray diffraction pattern, the orthorhombic (brookite) TiO 2 films with [130], [160] and [212] planes are seen from peaks at 2 θ = 33.5°, 61.7° and 75.7° on SiO 2 /Si and Si substrates, respectively. Current–voltage ( I – V ) characteristics reveal leakage current of ≈8.61 × 10 ‐8 and ≈4.05 × 10 ‐6 A/cm 2 at +2 V for film with and without SiO 2 passivation layer, respectively. Leakage current of TiO 2 /SiO 2 /Si device follows Fowler–Nordheim (FN) tunnelling at low field and Poole–Frenkel (PF) tunnelling at high field, whereas TiO 2 /Si device follows Schottky emission at low field and PF tunnelling at high field. Capacitance–voltage ( C – V ) characteristics reveal superior quality TiO 2 films with high dielectric constant of 44.5 and 35.8 for TiO 2 /SiO 2 /Si and TiO 2 /Si samples, respectively. Significant improvement in frequency dispersion and hysteresis voltage is observed for the sample with SiO 2 passivation layer. Introduction of SiO 2 passivation layer also improves interface traps and reliability of the device. Hence, a low cost novel alternative technique to grow high quality TiO 2 film on p‐type Si substrate with SiO 2 as passivation layer is suggested for development of high performance MOS devices.