HEMT Contact Opening Structure for Etch Damage Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing of high electron mobility transistors (HEMTs) faces challenges during the etching process, where insufficient etching can result in incomplete contact openings with residues of the insulating layer, while over-etching causes damage to the semiconductor layer, leading to defective contacts and yield loss.
Innovation Solution
A semiconductor structure is developed with an insulating layer having an extending portion that protrudes from the sidewall of the passivation layer and is adjacent to the surface of the stacked structure, directly contacting the contact structure. This configuration is achieved through a method involving the formation of a stacked structure, an insulating layer, a passivation layer, and an etching process using fluorine-based etching gases to create precise contact openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the etching process is extended to ensure complete penetration through the insulating layer, then the contact opening penetration is improved, but the semiconductor layer suffers from excessive loss and damage
Solution Approach 1:
The method performs preliminary actions by first forming a contact opening through the passivation layer, then selectively removing the insulating layer only in the contact opening region before depositing the contact electrode. This preliminary selective removal prevents the need for deep etching through the entire insulating layer thickness, thereby avoiding semiconductor layer damage while ensuring complete contact opening penetration.
Solution Approach 2:
The insulating layer removal process is segmented into two distinct steps: first removing the insulating layer in the contact opening region, then separately handling the passivation layer removal. This segmentation allows precise control over where and how much insulating material is removed, preventing over-etching damage to the semiconductor layer while ensuring adequate contact opening formation.
2Reliability
If the etching process is stopped early to preserve the semiconductor layer, then the semiconductor layer integrity is maintained, but the contact opening fails to penetrate through the insulating layer completely
Solution Approach 1:
The contact opening is preliminarily formed through the passivation layer before the insulating layer removal step. This preliminary action ensures that the contact opening penetration requirement is met early in the process, allowing subsequent insulating layer removal to be performed shallowly and selectively without risking incomplete penetration, while still preserving semiconductor layer integrity.
Solution Approach 2:
The process segments the opening formation into distinct stages: first creating the contact opening through the passivation layer, then selectively removing insulating material only where needed. This segmentation enables the contact opening to achieve complete penetration without requiring deep etching through the entire insulating layer thickness, thus preventing semiconductor layer damage.
3Reliability
If residual insulating layer remains on the semiconductor surface, then the etching process is safer for the semiconductor layer, but the contact quality deteriorates due to defective contact
Solution Approach 1:
The insulating layer is preliminarily removed in the contact opening region before contact electrode deposition. This preliminary removal ensures that the semiconductor surface is fully exposed and clean in the contact region, guaranteeing optimal contact quality. The process then proceeds to remove the passivation layer, maintaining safety margins against over-etching while ensuring contact integrity.
Solution Approach 2:
The insulating layer removal is segmented to occur only in the contact opening region, separate from the passivation layer removal process. This selective segmentation removes insulating residues precisely where they would affect contact quality, while preserving the safety buffer of remaining insulating material in other regions to prevent etching damage to the semiconductor layer.
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 solution ensures improved contact quality and increased production yield by preventing residues and damage during the etching process, while the extending portion of the insulating layer reduces leakage current and enhances the device's performance for high-frequency applications.
Implementation Method 1
performing an etching process to form an opening through the passivation layer and the insulating layer
Data Source
AI summary
A method for forming a semiconductor structure includes the steps of forming a stacked structure on a substrate, forming an insulating layer on the stacked structure, forming a passivation layer on the insulating layer, performing an etching process to form an opening through the passivation layer and the insulating layer to expose a portion of the stacked structure and an extending portion of the insulating layer, and forming a contact structure filling the opening and directly contacting the stacked structure, wherein the extending portion of the insulating layer is adjacent to a surface of the stacked structure directly contacting the contact structure.