N₂ Plasma Treatment Effects of SiN_x Buffer Layer for Low Temperature Process

Abstract

To adopt thin film transistor (TFT) type FRAM, low temperature process is necessary. SiN_x has good properties and advantages as a low temperature processed buffer layer. The SiN_x films were grown on the p-Si(100) substrate by the transformer coupled plasma chemical vapor deposition (TCP-CVD). By employing N₂ plasma treatment, interface traps such as mobile charges and injected charges were removed, hysteresis of capacitance-voltage (C-V) curve disappeared. After N₂ plasma treatment, a leakage current was decreased about 2 orders. The memory window of low temperature processed (at 550°C) metal-ferroelectric-insulator-silicon (MFIS) capacitor was as large as about 1.5 V.

Keywords:

• SiN_x buffer layer
• MFIS capacitor
• TFT type FRAM
• TCP-CVD
• N₂ plasma treatment

ACKNOWLEDGMENTS

This work was supported by Korea Industrial Technology Foundation.