Semiconductor Device With Expanded End Portion For Drive Current
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Solution Overview
Problem
Conventional fin transistors face challenges in maintaining drive current and threshold voltage as integration increases, leading to increased leakage current and reduced gate line reliability due to loss of device isolation film and difficulties in etching processes.
Innovation Solution
A semiconductor device with an expanded end portion protruding from the trench, featuring a gate electrode surrounding the active region, formed through anisotropic etching and epitaxial growth to increase channel length and reduce short channel effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the height of the fin pattern is increased to solve the reducing drive current problem, then the drive current is improved, but the loss of the device isolation film is increased causing over-etching and deterioration of device isolation characteristics
Solution Approach 1:
A mandrel structure is formed at the bottom of the trench before the fin pattern is created. This mandrel serves as a protective element that prevents over-etching of the device isolation film during subsequent etching processes, while still allowing the fin pattern to achieve the necessary height for adequate drive current
Solution Approach 2:
The mandrel acts as an intermediary protective structure between the etching process and the device isolation film. It absorbs the over-etching damage that would otherwise directly affect the device isolation film, enabling the fin pattern to reach required heights without compromising isolation characteristics
2Power
If the height of the fin pattern is increased to improve drive current, then the drive current is improved, but difficulty in subsequent gate formation process is increased causing defective etching and short circuiting of gates
Solution Approach 1:
The mandrel is formed in advance at the trench bottom before gate formation processes. This pre-formed structure provides a reference and protective element that guides subsequent etching operations, ensuring precise gate patterning even when fin patterns have increased height
Solution Approach 2:
The mandrel serves as an intermediary reference structure during gate formation etching. It prevents direct contact between the etching process and critical gate regions, reducing the risk of defective etching and short circuiting while allowing adequate fin height for drive current
3Reliability
If the channel length is extended to reduce short channel effects, then the threshold voltage control is improved, but the drive current is reduced
Solution Approach 1:
The active region is extended in the lateral dimension along the trench, creating an expanded end portion that increases the effective channel length for better threshold voltage control. Simultaneously, the vertical fin structure provides additional channel area that compensates for the drive current loss, achieving both goals through multi-dimensional structural optimization
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 enhances current drive capability and reduces short channel effects by increasing channel length and maintaining threshold voltage without increasing DIBL, while improving gate line reliability.
Implementation Method 1
formed through anisotropic etching and epitaxial growth
Implementation Method 2
formed through anisotropic etching and epitaxial growth to increase channel length
Data Source
AI summary
A semiconductor device includes a trench defined by etching a semiconductor substrate including a device isolation film and an active region, an active region protruded from a side and bottom of the trench, and a gate electrode surrounding the active region simultaneously while being buried in the trench.