Enhanced electrical and structural properties of stacked AlON∕HfO2 gate oxides on p-type Si substrates

• Published in: Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena Microelectronics and nanometer structures processing, measurement and phenomena, 2007-07, Vol.25 (4), p.1305-1309
• Main Authors: Choi, Wonjoon, Lee, Jonghyun, Yang, Jungyup, Kim, Juhyung, Hong, Jinpyo
• Format: Article
• Language: English
• ISSN: 1071-1023; 1520-8567
• DOI: 10.1116/1.2756546

The authors systematically investigated the stacked HfO2 gate oxides by inserting an ultrathin AlON layer between the amorphous HfO2 gate oxide and the p-type Si substrate. The inserted AlON layer was prepared with a remote rf plasma treatment method in order to reduce the effect of the interfacial layer easily formed between the HfO2 gate oxide and Si substrate while the HfO2 gate oxide was directly deposited on the Si substrate. The combination measurements of x-ray photoemission spectroscopy and high resolution transmission electron microscopy for the AlON∕HfO2 gate oxide clearly confirmed a significant decrease in the thickness of the interfacial layer. This structural improvement of stacked AlON∕HfO2 gate oxides corresponded well to more enhanced electrical characteristics of leakage current density (10−3A∕cm2), C-V hysteresis (20mV), and dielectric constant (20.4) than those of single HfO2 gate oxide (10−2A∕cm2, 40mV, and 14.1) grown directly on Si substrate. Therefore, it is expected that the optimized insertion of an additional ultrathin AlON layer can provide the realization of a high quality channel layer in a metal-oxide-semiconductor field effect transistor.