Abstract
The aim of this work was to develop a deposition process for a high-dielectric constant tantalum pentoxide for integrated capacitors. Thin films were deposited reactively on glass wafers using a radio-frequency magnetron sputtering cluster tool at various O2/Ar flow ratios. By using 2 MeV 4He+ backscattering spectroscopy and X-ray diffraction, the films obtained showed a stoichiometric orthorhombic β-Ta2O5 phase at 20% O2 in the sputtering gas flow. With low-frequency measurements (f=100 kHz), a 200×200-μm2 square metal–insulator–metal (MIM) capacitor with copper electrodes and a 340-nm thick dielectric gave a capacitance density of 0.066 μF/cm2, with a quality factor (Q) of 650. The value of the relative permittivity (εr) was approximately 25 determined from MIM capacitors of various sizes. The surface roughness of the 376-nm thick oxide film was found to be small: 0.255 nm. The largest measured capacitor (200×200 μm2) gave reasonable results at low frequencies. When the frequency was increased (100 kHz–20 GHz) only for the smaller capacitors (30×30 μm2) the capacitance remained constant. However, the Q values decreased of the smaller capacitors as a function of frequency. Processed tantalum pentoxide MIM capacitors possessed reasonable electrical properties below 2 GHz and good potential for further improvement.
Original language | English |
---|---|
Pages (from-to) | 392-397 |
Journal | Microelectronic Engineering |
Volume | 70 |
Issue number | 2-4 |
DOIs | |
Publication status | Published - 2003 |
MoE publication type | A1 Journal article-refereed |
Event | Materials for Advanced Metallization 2003 - La Londe Les Maures, France Duration: 9 Mar 2003 → 12 Mar 2003 |
Keywords
- reactive sputtering
- thin film capacitor
- thin films
- tantalum pentoxide
- tantalum