As the electronic device scale down, replacing conventional SiO2 with high dielectric constant material is very important. Due to its have high dielectric constant (£`// = 170, £`¡æ = 90), high refractive index (~2.5) and high chemical stability. TiO2 is a promising candidate for fabricating thin dielectrics in dynamic random access memory (DRAM) storage capacitors and as gate dielectrics of metal-oxide-semiconductor field effect transistor (MOSFET) without the problem of conventional SiO2 thickness scaling down in ULSI processes because of its high dielectric constant.
TiO2 thin films deposited on p-type (100) Si substrate were investigated by a cold wall horizontal MOCVD system using Ti(i-OC3H7)4, N2O as precursors in the deposition temperature range from 400 ¢J to 650 ¢J.
XRD results indicate that the structures of TiO2 films are polycrystalline and mixture of anatase and rutile phases coexist in the film at the deposition temperature of 650 ¢J. Electrical properties are strongly influenced by deposition temperature. The electrical properties of as-deposited TiO2 films can be improved by annealing treatment. The TiO2 film at the deposition temperature of 650 ¢J has the highest dielectric constant of 100.3 and at the deposition temperature of 550 oC has the lowest leakage current density of 2.07¡Ñ10-7 A/cm2 under the applied electric field of 5 MV/cm after annealing for 20 minutes at 750 ¢J in O2 ambient.
In order to obtain the better electrical properties of TiO2 films on Si substrate, LPD-SiO2 thin films were deposited on the polycrystalline MOCVD-TiO2 films. The minimum equivalent oxide thickness of LPD-SiO2/post-annealed TiO2 film is 51.13
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0713104-142834 |
| Date | 13 July 2004 |
| Creators | Wu, Tsung-Shiun |
| Contributors | none, none, none, Ming-Kwei Lee |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0713104-142834 |
| Rights | withheld, Copyright information available at source archive |
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