Schottky Electrode Ni Oxide Barrier Against Gate Leakage
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Solution Overview
Problem
In semiconductor devices, particularly high electron mobility transistors (HEMTs), the diffusion of nickel (Ni) from the Ni layer to the Au layer during high-temperature manufacturing and operation leads to the formation of nickel silicide in insulating films, deteriorating insulation properties and increasing gate leakage current.
Innovation Solution
A semiconductor device manufacturing method involving the formation of an Ni layer and an Au layer, followed by heat treatment at 350° C or more to deposit and oxidize Ni, forming a Ni oxide film on the surface of the Au layer, and then depositing an insulating film containing Si to prevent Ni diffusion and silicide formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ni layer is used in the Schottky electrode to form a large Schottky barrier, then the Schottky barrier height is improved, but Ni diffuses to the Au layer surface during high-temperature exposure and forms nickel silicide in the insulating film, deteriorating insulation property
Solution Approach 1:
The patent applies preliminary action by forming the Ni oxide film on the Au layer surface before the insulating film is deposited. This pre-formed oxide layer acts as a barrier that prevents Ni diffusion into the insulating film during subsequent high-temperature processing, while still allowing the underlying Ni layer to maintain its Schottky barrier function at the semiconductor interface
Solution Approach 2:
The Ni oxide film serves as an intermediary layer between the Au layer and the insulating film. This intermediate oxide layer blocks the diffusion path of Ni atoms, preventing them from reaching the Si-containing insulating film and forming harmful nickel silicide, while not interfering with the electrical function of the Schottky electrode
2Manufacturing precision
If heat treatment is performed at high temperature to improve crystallinity or other properties, then material quality is improved, but Ni diffusion accelerates and reaches the Au layer surface faster
Solution Approach 1:
The patent applies preliminary anti-action by pre-forming the Ni oxide film on the Au layer surface before high-temperature heat treatment. This oxide film is formed in advance to counteract and prevent the harmful Ni diffusion that would otherwise accelerate during subsequent high-temperature processing steps, allowing the heat treatment to proceed with improved material quality without the adverse diffusion effect
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively stabilizes the Ni oxide film, preventing nickel silicide formation and reducing gate leakage current, thereby enhancing the insulation and pressure resistance performance of the semiconductor device.
Implementation Method 1
performing heat treatment to the electrode at a temperature of 350° C. or more to deposit Ni at least at a part of a surface of the Au layer
Implementation Method 2
oxidize the deposited Ni
Implementation Method 3
Ni is gradually diffused from the Ni layer to the Au layer, and reaches the surface of the Au layer
Implementation Method 4
The Ni having reached the surface of the Au layer is diffused in the insulating film. In this case, the Ni is connected with the Si of the insulating film to form nickel silicide
Data Source
AI summary
A semiconductor device manufacturing method includes: forming an electrode including an Ni layer and an Au layer successively stacked on a semiconductor layer; forming a Ni oxide film by performing heat treatment to the electrode at a temperature of 350° C. or more to deposit Ni at least at a part of a surface of the Au layer and to oxidize the deposited Ni; and forming an insulating film in contact with the Ni oxide film and containing Si.