SOI Divot Buried Insulation for Gate Electrode Integrity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The reliability of semiconductor devices manufactured using SOI substrates is compromised due to the formation of divots in the element isolation region, which can lead to electrical connectivity issues and reduced device performance.
Innovation Solution
A buried insulating film is formed within the divots in the element isolation region to prevent the accumulation of etching residues and ensure proper formation of the gate electrode, thereby enhancing the structural integrity and reliability of the semiconductor device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a trench element isolation structure is formed by etching through the semiconductor layer and insulating layer, then the element isolation region can be effectively created, but divots are formed in the element isolation region which compromise device reliability
Solution Approach 1:
A buried insulating film is formed in advance within the element isolation region before the trench etching process. This preliminary action ensures that when divots are subsequently formed during trench etching, the buried insulating film is already in place to prevent etching residues from accumulating in the divots, thereby maintaining device reliability while achieving effective element isolation.
Solution Approach 2:
The buried insulating film acts as an intermediary material between the semiconductor layer and the trench structure. It specifically targets the divot regions to prevent harmful etching residues from accumulating, thus mediating between the conflicting requirements of precise trench formation and device reliability.
2Ease of manufacture
If the first insulating film is removed by etching to expose the semiconductor layer, then the gate insulating film can be formed properly, but etching residues may accumulate in divots and interfere with gate electrode formation
Solution Approach 1:
The buried insulating film is formed in advance within the element isolation region before the first insulating film removal process. This ensures that when divots are exposed during etching and subsequent gate electrode formation, the buried insulating film is already positioned to prevent etching residues from accumulating and interfering with the precise formation of the gate electrode.
3Reliability
If the element isolation region penetrates through the semiconductor layer and insulating layer to the support substrate, then effective element isolation is achieved, but divots form hollow parts that can trap etching residues
Solution Approach 1:
The buried insulating film serves as an intermediary material specifically placed within the element isolation region to address the harmful effect of divot formation. It fills and seals the hollow parts created by divots, preventing etching residues from accumulating in these trapped spaces, thus eliminating the harmful factor while preserving effective element isolation.
Solution Approach 2:
The invention converts the harmful divot structure into a beneficial configuration by filling it with buried insulating film. The divots, which originally trapped harmful etching residues, are transformed into sealed cavities containing benign insulating material, thereby converting a harmful structural feature into a beneficial one that maintains element isolation effectiveness.
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 buried insulating film effectively prevents etching residues from interfering with the gate electrode formation, improving the reliability and performance of the semiconductor device by maintaining the structural integrity of the element isolation region.
Implementation Method 1
A buried insulating film is formed in the hollow part (divot) of the element isolation region to prevent accumulation of etching residues
Implementation Method 2
forming a gate insulating film on a surface of the semiconductor layer
Data Source
AI summary
In an SOI substrate having a semiconductor substrate serving as a support substrate, an insulating layer on the semiconductor substrate and a semiconductor layer on the insulating layer, an element isolation region which penetrates the semiconductor layer and the insulating layer and whose bottom part reaches the semiconductor substrate is formed, and a gate electrode is formed on the semiconductor layer via a gate insulating film. A divot is formed in the element isolation region at a position adjacent to the semiconductor layer, and a buried insulating film is formed in the divot. The gate electrode includes a part formed on the semiconductor layer via the gate insulating film, a part located on the buried insulating film and a part located on the element isolation region.