Characterization of ultra-thin Y2O3 films as insulator of MFISFET structure

The possibility of ultra-thin Y2O3 (yttrium sesquioxide) films as insulator of metal ferroelectric insulator semiconductor (MFIS) structure was investigated. The ultra-thin Y2O3 films with thickness of 10–40 nm were fabricated on p-type Si (100) substrates by molecular beam epitaxy(MBE) in vacuum and subsequently submitted to rapid thermal processing (RTP) in air ambient at 700, 800 and 900 °C for 30 min, respectively. The films were characterized by X-ray diffractometry and Raman spectroscopy. High frequency capacitance—voltage (C—V) characteristics and current—voltage (I—V) characteristics of the Y2O3/Si structure were analyzed. A Raman peak of the Y2O3 thin films was observed at 378 cm−1. From the C—V data, these films exhibit dielectric constants ranging from 13 to 17.28, the hysteresis width (ΔVFB) ranging from 0.07 to 0.22 V and the density of trapped charges ranging from 1.65×1011 to 4.01×1011 cm−2. A leakage current of 4.75×10−8−9.0×10−6 A/cm2 at 1.5 MV/cm was observed. The results show that the Y2O3 buffer layers are suitable for non-volatile MFIS structure field-effect-transistors (FETs) memory application.