TY - JOUR
T1 - Wafer-to-wafer transfer process of barium strontium titanate for frequency tuning applications using laser pre-irradiation
AU - Samoto, Tetuo
AU - Hirano, Hideki
AU - Somekawa, Toshihiro
AU - Hikichi, Kousuke
AU - Fujita, Masayuki
AU - Esashi, Masayoshi
AU - Tanaka, Shuji
PY - 2015/3/1
Y1 - 2015/3/1
N2 - This paper describes laser-assisted film transfer technology for barium strontium titanate (BST) deposited on a sapphire substrate. BST is a promising ferroelectric material for varactors, which are required for frequency-tunable RF applications. However, the deposition temperature of BST (600 ∼ 700 °C) is too high for surface acoustic wave (SAW) substrates. In this study, BST grown on a sapphire substrate at 650 °C was transferred at low temperature (140 °C) to a borosilicate glass substrate as well as a LiTaO3 substrate. The transferred BST films were characterized as tunable capacitors. A key process in the BST film transfer technology is the laser pre-irradiation of a buffer Pt layer beneath BST from the backside of the sapphire substrate to weaken the BST-to-Pt adhesion. The mechanism of delamination at the BST/Pt interface is discussed using a simple 1D heat transfer model.
AB - This paper describes laser-assisted film transfer technology for barium strontium titanate (BST) deposited on a sapphire substrate. BST is a promising ferroelectric material for varactors, which are required for frequency-tunable RF applications. However, the deposition temperature of BST (600 ∼ 700 °C) is too high for surface acoustic wave (SAW) substrates. In this study, BST grown on a sapphire substrate at 650 °C was transferred at low temperature (140 °C) to a borosilicate glass substrate as well as a LiTaO3 substrate. The transferred BST films were characterized as tunable capacitors. A key process in the BST film transfer technology is the laser pre-irradiation of a buffer Pt layer beneath BST from the backside of the sapphire substrate to weaken the BST-to-Pt adhesion. The mechanism of delamination at the BST/Pt interface is discussed using a simple 1D heat transfer model.
KW - barium strontium titanate
KW - laser assisted transfer process
KW - lithium tantalate
KW - metal-insulator-metal variable capacitor
KW - wafertowafer bonding
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U2 - 10.1088/0960-1317/25/3/035015
DO - 10.1088/0960-1317/25/3/035015
M3 - Article
AN - SCOPUS:84923658692
VL - 25
JO - Journal of Micromechanics and Microengineering
JF - Journal of Micromechanics and Microengineering
SN - 0960-1317
IS - 3
M1 - 035015
ER -