Comb-Gate HV Structure for Punch-Through and Breakdown Control
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Solution Overview
Problem
As semiconductor circuits are adapted for high-voltage applications, issues arise with decreasing voltage performance due to punch-through between source and drain, leading to substrate leakage and voltage breakdown, which degrade device reliability.
Innovation Solution
The implementation of an HV device with a comb-like gate structure and alternately arranged doped regions and source regions, where the widths of the doped regions are greater than the source regions, improving carrier collection and reducing bulk resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple implantations with high doping concentrations are used to prevent punch-through and reduce source/drain resistance, then voltage performance is improved, but substrate leakage and voltage breakdown occur causing degradation of device reliability
Solution Approach 1:
The gate structure is segmented into multiple fingers arranged in a comb-like configuration. This segmentation allows the gate to better control the electric field distribution, preventing punch-through between source and drain while avoiding substrate leakage and voltage breakdown, thus improving device reliability without requiring multiple high-doping implantations
Solution Approach 2:
The invention introduces a lightly-doped drain region with a specific doping concentration range (1×10^16 to 1×10^18 atoms/cm³), which is lower than conventional drains. This local quality adjustment in the drain region prevents high-field effects and reduces substrate leakage while maintaining adequate voltage performance through the combined effect of the comb-like gate and the lightly-doped drain
2Productivity
If the device is downscaled to reduce size, then integration density is improved, but voltage performance decreases due to punch-through between source and drain
Solution Approach 1:
The comb-like gate structure with multiple fingers provides enhanced control over the channel region even in downscaled devices. The segmented gate configuration increases the effective gate control area, preventing punch-through between source and drain while allowing the device to maintain compact dimensions for high integration density
Solution Approach 2:
The invention transitions from a conventional planar gate to a three-dimensional comb-like gate structure. This dimensional change increases the gate's control capability without proportionally increasing the device footprint, enabling voltage performance maintenance during downsaling while achieving high integration density
3Ease of manufacture
If standard MOS fabrication process flows are used, then manufacturing simplicity is maintained, but substantial substrate leakage and voltage breakdown occur
Solution Approach 1:
The invention modifies the standard MOS fabrication by introducing a lightly-doped drain region with specific doping characteristics. This local modification can be integrated into existing fabrication processes while preventing substrate leakage and voltage breakdown, maintaining manufacturing simplicity with minimal process changes
Data Source
AI summary
A high-voltage device includes a substrate, a gate structure over the substrate, a drain region disposed on a first side of the gate structure, a plurality of source regions disposed on a second side of the gate structure, and a plurality of doped regions disposed on the second side of the gate structure. The gate structure includes a plurality of first portions and a plurality of second portions alternately arranged. Width of the first portions are greater than widths of the second portions. The source regions are adjacent to the first portions of the gate structures, and the doped regions are adjacent to the second portions of the gate structure. The drain region and the source regions include dopants of a first conductivity type, and the doped regions include dopants of a second conductivity type. The first conductivity type and the second conductivity type are complementary to each other.