Improving the Electrical Properties of Lanthanum Silicate Films on Ge Metal Oxide Semiconductor Capacitors by Adopting Interfacial Barrier and Capping Layers

• Published in: ACS applied materials & interfaces 2014-05, Vol.6 (10), p.7885-7894
• Main Authors: Choi, Yu Jin, Lim, Hajin, Lee, Suhyeong, Suh, Sungin, Kim, Joon Rae, Jung, Hyung-Suk, Park, Sanghyun, Lee, Jong Ho, Kim, Seong Gyeong, Hwang, Cheol Seong, Kim, HyeongJoon
• Format: Article
• Language: English
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/am5012172

The electrical properties of La-silicate films grown by atomic layer deposition (ALD) on Ge substrates with different film configurations, such as various Si concentrations, Al2O3interfacial passivation layers, and SiO2 capping layers, were examined. La-silicate thin films were deposited using alternating injections of the La­[N­{Si­(CH3)3}2]3 precursor with O3 as the La and O precursors, respectively, at a substrate temperature of 310 °C. The Si concentration in the La-silicate films was further controlled by adding ALD cycles of SiO2. For comparison, La2O3 films were also grown using [La­( i PrCp)3] and O3 as the La precursor and oxygen source, respectively, at the identical substrate temperature. The capacitance–voltage (C–V) hysteresis decreased with an increasing Si concentration in the La-silicate films, although the films showed a slight increase in the capacitance equivalent oxide thickness. The adoption of Al2O3 at the interface as a passivation layer resulted in lower C–V hysteresis and a low leakage current density. The C–V hysteresis voltages of the La-silicate films with Al2O3 passivation and SiO2 capping layers was significantly decreased to ∼0.1 V, whereas the single layer La-silicate film showed a hysteresis voltage as large as ∼1.0 V.