The effect of leakage current on retention time of Metal-Ferroelectric-Insulator-Silicon(MFIS) Capacitors and Field-Effect Transistors

• Main Authors: Kun-yung Kang, 康琨永
• Other Authors: Joseph Ya-Min Lee
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/83125896443442220063

碩士 === 國立清華大學 === 電子工程研究所 === 95 === Abstract Al/ Pb (Zr0.53, Ti0.47) O3 (PZT) /ZrO2/Si metal-ferroelectric-insulator semiconductor (MFIS) capacitors and transistors were fabricated. A surface treatment method was used to passivate ZrO2/Si interface and to reduce the leakage current. The wafers were given a H2O2 pre-treatment before ZrO2 deposition and a HCl treatment after deposition. The leakage current density of Al/PZT/ZrO2/Si capacitors was improved to 5.4x10-6 A/cm2 at a sweep voltage of 5 V. The retention time of Al/PZT/ZrO2/Si capacitors after these surface treatments was increased from 13.3 hours to 17.1 days. The largest memory window of 0.7 V was obtained at a sweep voltage of 8 V. The gate leakage current density of FeFETs at 5 V was reduced to 5x10-6 A/cm2. The electron mobility is 267 cm2/V-s. The subthreshold slope was improved to 106 mV/dec. The FeFETs maintain a threshold voltage window of about 1.1 V after an elapsed time of 3000 sec. The improved retention time is attributed to the reduced gate leakage current.