Fabrication and characterization of metal-insulator-semiconductor structures by direct nitridation of InP surfaces

Abstract

We have fabricated InP metal-insulator-semiconductor (MIS) structures with direct nitridation of InP surfaces. The nitridation is performed by exposing InP surfaces to electron cyclotron resonance (ECR) N2 plasma. The formation of InP oxynitride layers with the thickness of around 1.5 nm is confirmed by transmission electron microscope images and x-ray photoelectron spectroscopy analysis. It is found that the surface nitridation drastically reduces the hysteresis of the C-V curves of SiO2/oxynitride/InP MIS capacitors, compared with the MIS capacitors without oxynitrides, indicating the reduction of slow traps inside InP native oxides. The nitridation under the rf power of 500 W can lead to the hysteresis down to 10 mV and the VFB shift down to −0.36 V. These results provide the experimental evidences for the effectiveness of ECR N2 plasma nitridation of InP and the insertion of the oxynitrided InP interfacial layers in terms of the InP MIS interface control.