METHOD OF DEPOSITING GATE DIELECTRIC, METHOD OF FABRICATING MIS CAPACITOR, AND MIS CAPACITOR

摘要

A method of depositing a gate dielectric, a method of fabricating a MIS capacitor and a MIS capacitor are provided. In the method of depositing the gate dielectric, firstly, performing pretreatment to the surface of a semiconductor substrate by employing O2 plasma and plasma containing nitrogen element, to form an oxide layer containing nitrogen on the surface of the semiconductor; next, growing a gate dielectric layer having a high dielectric constant on the surface of the oxide layer containing nitrogen by a plasma enhanced atomic layer deposition (PEALD) method, and in the process of growing the gate dielectric layer, the oxide layer is converted into a buffer layer having a dielectric constant higher than that of SiO2; then, forming metal electrodes on the upper and lower surfaces of the formed semiconductor structure, thus forming a MIS capacitor. The presence of the buffer layer can effectively improve interface characteristics between the semiconductor material and the high-k gate dielectric layer, further, can reduce the increase of equivalent oxide thickness (EOT), and can improve the electrical performance.