Structural and Electrical Properties of Crystalline CeO₂ Films Formed by Metalorganic Decomposition

Abstract

Crystalline CeO2 films were formed on a Si (100) substrate by metalorganic decomposition at temparatures ranging from 600°C to 800°C. As-deposited films were in the amorphous state and were completely transformed to crystalline CeO2 above 600°C. However, during crystallization in oxygen atomosphere, a reaction between CeO2 and Si occurred at the interface, which resulted in the formation of a thin interfacial SiO2 layer. Capacitance-voltage measurement on these films showed good dielectric properties with a dielectric constant of 15, which is more than three times higher than that of SiO2. The modified structure of CeO2/SiO2/Si is expected to be suitable for the dielectric layer in an integrated circuit, in place of conventional dielectric films such as those of SiO2 or Si3N4.

Physical characterization of post-deposition annealed metal-organic decomposed cerium oxide film spin-coated on 4H-silicon carbide

“…Four diffraction peaks, which were ascribed to cubic phases of CeO 2 , were detected at (1 1 1), (2 0 0), (2 2 0) and (3 1 1). These peaks were similar to those reported in CeO 2 -Si system [35,43]. The CeO 2 (2 0 0) diffraction peak becomes sharper with the increase in annealing temperature but not much changes in intensity for other CeO 2 peaks.…”

“…These properties have promoted CeO 2 as an alternative gate to SiO 2 . Previously, a large body of work has been carried out on CeO 2 film deposited on Si substrate using various deposition techniques, such as spray pyrolysis, electron beam evaporation, reactive sputtering, ion-beam sputtering, metal-organic decomposition (MOD), pulsed laser deposition and others [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. Among these techniques, MOD method appears to be a convenient route due to its simplicity in processing control and accuracy in composition control [49] if compared to vacuum techniques, such as reactive sputtering and electron beam evaporation [34,37,40].…”

“…In addition, the effects of post-deposition annealing in oxygen ambient have been studied on CeO 2 film deposited on Si substrate [35,59]. Interestingly, a SiO 2 interfacial layer was formed between the MOD-derived CeO 2 and Si substrate [35,59].…”

“…Interestingly, a SiO 2 interfacial layer was formed between the MOD-derived CeO 2 and Si substrate [35,59]. This is due to the ability of CeO 2 to transform to Ce 2 O 3 and vice versa [33], in which this phase transformation happens either in reducing or oxidizing conditions [48].…”

In situ Raman characterization of CeO2 thin films sputtered on (111) Si in order to optimize the post growth annealing parameters

“…Some papers have shown that the crystalline quality of the CeO 2 films grown on (1 1 1) Si substrate is better for a high growth temperature [24] and that the crystallinity is improved by a post deposition rapid thermal annealing [35]. Most of the time, studies on the influence of thermal annealing highlight the impact of the annealing time and annealing temperature on the crystallinity [36] and on the electrical properties [37] of the CeO 2 layers. All these papers show the importance of the post-growth annealing in microelectronic process.…”