Back Gate Contact Epitaxy for SOI Transistor Process Simplification
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Solution Overview
Problem
The formation of back gate contacts in semiconductor devices, particularly in SOI technology, often damages existing structures and requires additional protective layers and polysilicon filling, complicating the manufacturing process and increasing costs.
Innovation Solution
The use of an epitaxial process to form back gate contacts without damaging existing structures, eliminating the need for additional protective layers and polysilicon filling, by raising epitaxial parts from the surface of the back gate electrode and source/drain regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to form back gate contacts, then electrical connection is achieved, but existing structures are damaged and additional protective layers and polysilicon filling are required
Solution Approach 1:
The method performs preliminary protective actions by forming a protective film over the buried oxide layer before back gate contact formation, and uses selective etching to expose only the necessary portions of the back gate electrode. This preliminary protection prevents damage to existing structures during subsequent processing steps.
Solution Approach 2:
A protective film is introduced as an intermediary layer between the back gate contact formation process and the buried oxide layer. This intermediary protects the sensitive buried oxide structure from damage while allowing the back gate contact to be formed, eliminating the need for additional protective layers after the fact.
2Reliability
If additional protective layers and polysilicon filling are used to form back gate contacts, then structure protection is achieved, but manufacturing cost and process complexity increase
Solution Approach 1:
The method extracts and removes the unnecessary polysilicon layer through selective etching, exposing the back gate electrode directly. This eliminates the need for additional polysilicon filling steps while maintaining structure protection through the previously formed protective film.
Solution Approach 2:
The unnecessary polysilicon layer is discarded through selective removal, and the protective film is recovered/reused to protect the buried oxide structure throughout the process. This reduces material waste and simplifies the overall manufacturing process by eliminating redundant steps.
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
This simplifies the manufacturing process, reduces costs, and ensures the integrity of existing structures during back gate contact formation in semiconductor devices.
Implementation Method 1
performing a selective epitaxy to the exposed portion of the back gate electrode, the source region and the drain region to form an epitaxial part raised from the surface of the back gate electrode, so as to form a back gate contact
Data Source
AI summary
The invention relates to a transistor, a semiconductor device comprising the transistor and manufacturing methods for the transistor and the semiconductor device. The transistor according to the invention comprises: a substrate comprising at least a base layer, a first semiconductor layer, an insulating layer and a second semiconductor layer stacked sequentially; a gate stack formed on the second semiconductor layer; a source region and a drain region located on both sides of the gate stack respectively; a back gate comprising a back gate dielectric and a back gate electrode formed by the insulating layer and the first semiconductor layer, respectively; and a back gate contact formed on a portion of the back gate electrode. The back gate contact comprises an epitaxial part raised from the surface of the back gate electrode, and each of the source region and the drain region comprises an epitaxial part raised from the surface of the second semiconductor layer. As compared to a conventional transistor, the manufacturing process of the transistor of the invention is simplified and the cost of manufacture is reduced.