Semiconductor Mesa Doping Profile for Short Channel Effect Suppression
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Solution Overview
Problem
Conventional semiconductor devices with gate trenches face challenges in suppressing the short channel effect, which affects the effective channel length and device performance.
Innovation Solution
The semiconductor device incorporates a mesa portion with specific doping concentration profiles, including an intermediate region with a higher doping concentration of the second conductivity type, strategically positioned between the base and accumulation regions, to control dopant diffusion and reduce the short channel effect. This configuration involves multiple implantation and annealing steps to optimize the doping concentration distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a gate trench is used in conventional semiconductor devices, then the device structure is simplified and manufacturing is easier, but the short channel effect cannot be effectively suppressed
Solution Approach 1:
The patent applies local quality by creating an intermediate region with higher doping concentration specifically at the center of the mesa portion, while maintaining lower doping concentration at the trench contact portions. This localized doping concentration variation suppresses the short channel effect in the critical center region without compromising the overall device structure or manufacturing simplicity.
Solution Approach 2:
The patent changes the doping concentration parameter by introducing an intermediate region with higher doping concentration of the second conductivity type. This parameter change in the vertical depth direction creates a doping profile that effectively suppresses the short channel effect while maintaining the gate trench structure for ease of manufacture.
2Reliability
If the doping concentration is increased to suppress the short channel effect, then the channel control improves, but the dopant diffusion increases and affects adjacent regions
Solution Approach 1:
The intermediate region is localized at the center of the mesa portion in the vertical depth direction, creating a doping concentration distribution that is high where needed for channel control and low at the trench contact portions. This spatial differentiation prevents dopant diffusion into adjacent regions while maintaining effective channel control.
Solution Approach 2:
The patent addresses dopant diffusion by transitioning from a two-dimensional planar doping approach to a three-dimensional vertical doping profile. The intermediate region is positioned at a specific depth range (0.5-2.0 μm from the surface) and width (0.1-0.5 μm), creating a controlled doping distribution in the vertical dimension that suppresses lateral dopant diffusion.
3Manufacturing precision
If multiple implantation and annealing steps are used to optimize doping distribution, then the doping concentration profile precision improves, but the manufacturing process complexity increases
Solution Approach 1:
The base region is formed first through preliminary ion implantation and annealing, establishing the fundamental doping structure. Subsequently, the intermediate region is formed by additional ion implantation of the second conductivity type dopant, followed by a second annealing process. This sequential preliminary action allows precise control of the doping profile while maintaining a systematic manufacturing approach.
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 proposed design effectively suppresses the short channel effect, maintains the carrier injection-enhancement effect, and reduces the ON voltage by controlling dopant diffusion and channel characteristics.
Implementation Method 1
controlling dopant diffusion and channel characteristics
Implementation Method 2
multiple implantation and annealing steps to optimize the doping concentration distribution
Implementation Method 3
multiple implantation and annealing steps to optimize the doping concentration distribution
Data Source
AI summary
Provided is a semiconductor device, wherein at least one mesa portion contacting a gate trench portion thereof comprises: a first conductivity type emitter region with a doping concentration higher than a drift region, exposed on the top of the substrate and contacting the gate trench portion; a second conductivity type base region under the emitter region, contacting the trench portion, having a first peak in a doping concentration distribution in a depth direction of the substrate; a first conductivity type accumulation region under the base region, having a doping concentration higher than the drift region; and a second conductivity type intermediate region at a depth position between the base region and the accumulation region, having at least one of a second peak and a kink portion from the first peak to a depth position of a bottom of the trench portion in the doping concentration distribution in the depth direction.