Trench-Gate Transistor Side Wall Insulation for Breakdown Resistance
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Solution Overview
Problem
Conventional trench-gate-type transistors suffer from electric breakdown resistance defects due to misalignment between the gate electrode and source/drain region, leading to compromised DRAM refresh characteristics and transistor performance.
Innovation Solution
Incorporating a side wall insulating film and an epitaxial layer with impurity diffusion layers to create a semiconductor device where the side wall insulating film separates the gate electrode from the source/drain region, minimizing electric field intensity and preventing breakdown resistance defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a trench-gate-type transistor is used to maintain effective channel length, then miniaturization and precision are improved, but electric breakdown resistance deteriorates due to misalignment between gate electrode and source/drain region
Solution Approach 1:
A side wall insulating film is introduced as an intermediary layer between the gate electrode and the source/drain region. This side wall insulating film is formed on the side surface of the gate electrode, creating a physical barrier that prevents direct contact and reduces the electric field intensity between the gate electrode and source/drain region, thereby improving electric breakdown resistance while maintaining the trench-gate structure
Solution Approach 2:
The insulation structure is extended from a two-dimensional planar configuration to a three-dimensional structure by forming a side wall insulating film on the vertical side surface of the gate electrode. This adds a vertical dimension to the insulation, providing protection against electric breakdown even when misalignment occurs in the horizontal plane
2Area of stationary object
If gate electrode and source/drain region are placed in close proximity to minimize device area, then device density is improved, but electric breakdown resistance deteriorates
Solution Approach 1:
The side wall insulating film serves as a mediator that enables close placement of the source/drain region to the gate electrode while maintaining adequate electric breakdown resistance. The insulating film fills the space between the gate electrode and source/drain region, allowing minimal spacing without compromising reliability
Data Source
AI summary
A semiconductor device is provide with a semiconductor substrate, a groove formed in the semiconductor substrate, a gate insulting film formed on the inner wall of the groove, a gate electrode formed in the groove, and a source/drain region and an LDD region arranged in the direction that is substantially orthogonal to the substrate surface of the semiconductor substrate.