Semiconductor Etch Stop Layer for Precise Gate Formation
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Solution Overview
Problem
Existing semiconductor manufacturing processes result in low carrier mobility in MOSFET devices due to inaccurate etching depth control during the formation of the gate electrode insulating layer and gate electrode, which damages the channel layer and reduces performance.
Innovation Solution
A semiconductor structure with an etch stop layer between the channel layer and the P-type semiconductor layer, allowing precise etching control and preventing damage to the channel layer, along with an anti-alloy scattering layer and P-type doped materials in the etch stop layer to enhance carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If etching is performed to remove P-type semiconductor layer in gate region, then gate electrode insulating layer and gate electrode can be formed, but etching depth cannot be accurately controlled and channel layer is damaged
Solution Approach 1:
An etch stop layer is introduced between the P-type semiconductor layer and the channel layer. This intermediary layer has different etching characteristics that allow the etching process to stop automatically at the desired depth, preventing damage to the channel layer while enabling complete removal of the P-type semiconductor layer in the gate region.
Solution Approach 2:
The etch stop layer is formed in advance before the P-type semiconductor layer deposition. This preliminary action prepares the structure for subsequent etching by establishing a depth reference that will control the etching process, ensuring that the channel layer is protected while the P-type layer is removed where needed.
2Ease of manufacture
If P-type semiconductor layer is removed in gate region, then gate electrode can be formed, but carrier mobility in channel is reduced due to channel layer damage
Solution Approach 1:
The etch stop layer acts as a protective intermediary that allows the etching process to proceed without damaging the channel layer. By controlling the etching depth to stop at the etch stop layer, the channel layer integrity is maintained, preserving carrier mobility while still enabling gate electrode formation.
3Ease of manufacture
If etching depth is increased to remove P-type semiconductor layer, then gate structure can be formed, but channel layer surface is damaged
Solution Approach 1:
The etch stop layer serves as a mediator that absorbs the harmful effect of excessive etching. It is positioned between the P-type semiconductor layer and the channel layer, allowing the etching process to remove the P-type layer completely while stopping before damaging the channel layer surface.
Solution Approach 2:
The etch stop layer provides beforehand cushioning by being placed in advance to protect the channel layer. It acts as a sacrificial layer that can be etched away along with the P-type semiconductor layer, cushioning the channel layer from direct exposure to the etching process and preventing surface damage.
Data Source
AI summary
The present disclosure provides a semiconductor structure and a manufacturing method thereof. The semiconductor structure includes: a semiconductor substrate, a back barrier layer, a channel layer and an etch stop layer arranged from bottom to up; and a P-type semiconductor layer located in a source region and a drain region on the etch stop layer. Due to the setting of the etch stop layer, when the P-type semiconductor layer in the gate region is removed by etching, etching can be stopped at the etch stop layer, and the etching depth can be accurately controlled without causing etching damage to the channel layer. The carrier mobility of holes in the channel in the semiconductor structure is improved, and yield and performance of the device are improved.