Novel capacitor process using diffusion barrier rounded by Si/sub 3/N/sub 4/ spacer for high density FRAM device
| Autor: | Suk Ho Joo, D. J. Jung, Hyunho Kim, Yong-Tak Lee, B.J. Koo, Sung Yung Lee, Kinam Kim, Yoon J. Song |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Materials science
Diffusion barrier business.industry Contact resistance Analytical chemistry Electrical engineering Substrate (electronics) Ferroelectricity Ferroelectric capacitor Electronic Optical and Magnetic Materials Barrier layer Etching (microfabrication) Electrode Electrical and Electronic Engineering business |
| Zdroj: | IEEE Electron Device Letters. 21:280-282 |
| ISSN: | 1558-0563 0741-3106 |
| Popis: | A novel capacitor process was successfully implemented in 4 Mb FRAM device by developing a barrier layer rounded by Si/sub 3/N/sub 4/ spacer (BRS) scheme. Using this process, it is possible to eliminate an undesired barrier etching damage, which is a major role in degrading ferroelectric properties. The novel capacitor process was generated by etching an Ir barrier layer and rounding the barrier by a Si/sub 3/N/sub 4/ spacer before preparing Pb(Zr/sub 1-x/Ti/sub x/)O/sub 3/ (PZT) films. It was observed that uniform sol-gel derived PZT films were prepared on the patterned Ir substrate by using Si/sub 3/N/sub 4/ spacer, which provides a smooth edge of the patterned cell. The contact resistance between bottom electrode and polysilicon plug after full integration was monitored below 700 /spl Omega/ per contact with contact size 0.6/spl times/0.6 (/spl mu/m/sup 2/). Compared to the ferroelectric capacitor damaged by barrier etching, the novel Pb(Zr/sub 1-x/Ti/sub x/)O/sub 3/ (PZT) capacitor exhibited a well-saturated Q-V curve. The fully processed novel capacitor having 1.2/spl times/1.2 (/spl mu/m/sup 2/) effective area displayed remnant polarization of 14 (/spl mu/C/cm/sup 2/) at an operating voltage of 3.0 V. The BRS ferroelectric capacitor showed a reliable retention property until 100 h at 125/spl deg/C. Same state retention (Qss) was stable with time up to 100 h while opposite state retention (Qos) showed a log-linear decay rate at 125/spl deg/C thermal stress. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|