Effective formation of interface controlled Y2O3 thin film on Si(100) in a metal-(ferroelectric)-insulator-semiconductor structure

• Published in: Microelectronic engineering 2008-08, Vol.85 (8), p.1781-1785
• Main Authors: KWON, Kwang-Ho, CHANG KI LEE, YANG, Jun-Kyu, SUN GYU CHOI, HO JUNG CHANGE, JEON, Hyeongtag, PARK, Hyung-Ho
• Format: Article
• Language: English
• Subjects: Applied sciences; Compound structure devices; Electronics; Exact sciences and technology; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2008.05.004

Yttrium was deposited on the chemical oxide of Si and annealed under vacuum to control the interface for the formation of Y2O3 as an insulating barrier to construct a metal-ferroelectric-insulator-semiconductor structure. Two different pre-annealing temperatures of 600 and 700 deg C were chosen to investigate the effect of the interface state formed after the pre-annealing step on the successive formation of Y2O3 insulator and Nd2Ti2O7 (NTO) ferroelectric layer through annealing under an oxygen atmosphere at 800 deg C. Pre-anneal treatments of Y-metal/chemical-SiO2/Si at 600 and 700 deg C induced a formation of Y2O3 and Y-silicate, respectively. The difference in the pre-anneal temperature induced almost no change in the electrical properties of the Y2O3/interface/Si system, but degraded properties were observed in the NTO/Y2O3/interface/Si system pre-annealed at 600 deg C when compared with the sample pre-annealed at 700 deg C. C-V characteristics of the NTO/Y2O3/Si structured system showed a clockwise direction of hysteresis, and this gap could be used as a memory window for a ferroelectric-gate. A smaller hysteric gap and electrical breakdown values were observed in the NTO/Y2O3/Si system pre-annealed at 600 deg C, and this was due to an unintentional distribution of the applied field from the presence of an interfacial layer containing Y-silicate and SiO2 phases.