Method for preparing metal-oxide-semiconductor capacitor on germanium substrate

Abstract

The invention discloses a method for preparing an MOS (metal-oxide-semiconductor) capacitor on germanium substrate, comprising the following steps: sequentially depositing silicon nitride film and hafnium nitride film in the atmosphere of argon and nitrogen with RF-magnetron reaction sputtering method on a germanium wafer after cleaned; carrying out rapid thermal annealing in the atmosphere of nitrogen; forming photoresist patterns through glue spreading, exposing and developing; depositing metal electrode material with RF-magnetron reaction sputtering method; peeling the metal electrode material to form electrode patterns; sputtering a layer of metal aluminum at the back of the germanium substrate to reduce the contact resistance of the back; and finally annealing for metallization in a furnace tube in the atmosphere of nitrogen. The silicon nitride film is used as diffusion barrier layer, thereby solving the problem of producing oxides containing a large amount of defective germanium in annealing process after deposition of gate dielectric and annealing process after the formation of metal electrode, reducing fixed charges at interface and charge trapping center, and obtaining an MOS capacitor with excellent electrical properties.

Description

technical field [0001] The invention relates to the technical field of preparing semiconductor devices with nanometer feature size, in particular to a method for preparing a metal-oxide-semiconductor (MOS) capacitor on a germanium substrate by using a hafnium-based high-permittivity gate dielectric. Background technique [0002] Historically, the first transistors and the first integrated circuits were fabricated using germanium substrate materials. Due to the thermodynamic instability and water-soluble characteristics of germanium oxide, it is not suitable as a gate dielectric material; while silicon dioxide has excellent physical and electrical properties, so the metal-oxidized silicon substrate is used Thin-semiconductor transistors (MOSFETs) have been extensively studied and applied in the past forty years. Over the past 40 years, integrated circuit technology has continued to develop according to Moore's law, the feature size has been continuously reduced, and the inte...

AI Technical Summary

Problems solved by technology

[0006] In view of this, the main purpose of the present invention is to provide a method for preparing MOS capacitors on a germanium substrate, so as to solve the problem of generating germanium containing a large number of defect states in the annealing process after gate dielectric deposition and metal electrode formation. The problem of oxides, reducing the fixed charge and charge trapping center at the interface, and obtaining MOS capacitors with excellent electrical properties

Images