Characteristics of an N2O Radical Oxide Grown by using Electron Cyclotron Resonance Radical Oxidation and Its Application to 50-nm MOSFETs with Floating Polysilicon Spacers

Abstract

We have developed a process of growing a radical oxide by using electron cyclotron resonance (ECR) N2O radical oxidation at 400 degreesC. The radical oxide was grown on a silicon substrate and then characterized. These oxides had large breakdown fields and small electron-trapping characteristics. The charge-to-breakdown characteristics (Q(BD)) up to 600 C/cm(2) under a negative constant current density of -40 mA/cm(2) were obtained. In order to investigate the possibility of using the radical oxide as a gate dielectric, we fabricated a NMOSFET with a floating side-gate structure, adopting this ECR N2O radical oxide as the gate dielectric and the inter-poly dielectric. Reasonable IV characteristics were obtained from the fabricated 50-nm device. From these results, the on-current I-ON was about 400 muA/mum at V-GS - V-TH = 1.5 V and V-DS = 1.5 V. This radical oxide can be applied to sub-0.1-mum Complementary Metal Oxide Semiconductor (CMOS) technology by optimizing the process conditions.