Semiconductor Device Gate Side Opening for HEMT Current Collapse
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Solution Overview
Problem
Current nitride semiconductor high-electron mobility transistors (HEMTs) experience current collapse due to electron trapping at the semiconductor surface, caused by the shrinkage of protection films leading to clearance formation between the gate electrode and the protection film, which results in electric field concentration and trapped electrons.
Innovation Solution
Incorporating gate side openings in the protection film between the source and drain electrodes and the gate electrode, which reduces the impact of the protection film's shrinkage on the semiconductor surface, thereby minimizing electron trapping and current collapse by maintaining a shorter distance between the gate electrode and the gate side opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If heat treatment and ultraviolet light irradiation are performed to densify the protection film, then the protection film becomes denser and more protective, but the protection film shrinks and forms clearance with the gate electrode side faces, exposing the semiconductor surface
Solution Approach 1:
The patent applies preliminary anti-action by forming a gate side opening in the protection film before heat treatment and ultraviolet light irradiation are performed. This pre-formed opening prevents the protection film from contacting the gate electrode side faces during subsequent shrinkage, thereby preventing clearance formation and semiconductor surface exposure while still allowing the protection film to be densified through the planned treatments.
2Area of stationary object
If the protection film is made to contact the gate electrode side faces, then complete coverage is achieved, but electric field concentration occurs at the gate electrode lower end and drain-side fringe, causing electron trapping and current collapse
Solution Approach 1:
The patent applies the taking out principle by extracting the gate electrode side faces from the contact region with the protection film. A gate side opening is formed in the protection film, removing the portion that would otherwise contact the gate electrode side faces. This prevents electric field concentration and electron trapping at these locations, eliminating current collapse while maintaining protection film coverage over other critical areas.
3Strength
If the protection film is shrunk through heat treatment and ultraviolet light irradiation, then the film is densified for better protection, but clearance forms between the protection film and gate electrode, exposing the semiconductor surface to electron trapping
Solution Approach 1:
The patent applies preliminary anti-action by pre-forming a gate side opening in the protection film before densification treatments. This ensures that when the protection film shrinks during heat treatment and ultraviolet light irradiation, the gate electrode side faces remain excluded from contact, preventing semiconductor surface exposure and electron trapping while maintaining the protective strength gains from film densification.
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 gate side openings effectively suppress current collapse by preventing clearance formation between the protection film and the gate electrode, maintaining device performance and reducing electron trapping, while allowing for controlled electric field distribution.
Implementation Method 1
After these treatments, the protection film 35 shrinks and a clearance 90 is formed between the protection film 35 and each of the side faces of the lower end of the gate electrode 40
Data Source
AI summary
A semiconductor device having a source electrode and a drain electrode formed over a semiconductor substrate, a gate electrode formed over the semiconductor substrate and disposed between the source electrode and the drain electrode, a protection film made of an insulating material and formed between the source electrode and the gate electrode and between the drain electrode and the gate electrode, and a gate side opening formed at least in one of a portion of the protection film-between the source electrode and the gate electrode and a portion of the protection film between the drain electrode and the gate electrode and disposed away from all of the gate electrode, the source electrode and the drain electrode.