Semiconductor Contact Trench Shallow Doping Peak
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Solution Overview
Problem
As semiconductor devices are miniaturized, the P+ type contact layer can affect the threshold voltage (Vth), leading to issues with latch-ups and increased ON voltage due to its positioning and doping concentration relative to the source region.
Innovation Solution
A semiconductor device design featuring a contact trench with a contact layer of the second conductivity type positioned shallower than the source region's lower end, having multiple peaks of doping concentration, and extending in the direction of trench portions, with the contact layer's lower end positioned deeper than the source region's lower end, to minimize the impact on threshold voltage and suppress latch-ups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a P+ type contact layer is provided below the contact trench in conventional semiconductor devices, then contact properties are improved, but the threshold voltage is adversely affected and latch-ups occur due to the contact layer's positioning and doping concentration
Solution Approach 1:
The contact layer is designed with non-uniform doping concentration featuring a peak positioned shallower than the source region's lower end, creating localized high-doping regions that optimize contact properties while minimizing adverse effects on threshold voltage. This local quality variation allows different depths to serve different functions: shallow peaks for contact performance, deeper regions for reduced threshold voltage impact.
Solution Approach 2:
The invention changes the doping concentration parameter by introducing multiple peaks with specific depth positions, where the peak position is shallower than the source region's lower end. This parameter modification transforms the contact layer's electrical characteristics, enabling it to provide good contact properties while reducing the harmful effects on threshold voltage and suppressing latch-up phenomena.
2Productivity
If semiconductor devices are miniaturized with narrowed mesa width, then device integration is improved, but the contact layer's influence on threshold voltage increases
Solution Approach 1:
By concentrating the doping peak shallower than the source region's lower end, the contact layer's high-doping region is localized to where it is most needed for contact properties, while the deeper regions have reduced doping concentration. This local quality differentiation allows miniaturization without proportionally increasing threshold voltage influence, as the critical high-doping zone is confined to a specific depth range.
Solution Approach 2:
The invention addresses the two-dimensional constraint of miniaturized mesa width by introducing a depth dimension solution. Instead of horizontally expanding the contact layer to reduce threshold voltage influence (which would increase area), the doping concentration is strategically distributed in the depth direction with peaks positioned shallower than the source region's lower end, effectively using the vertical dimension to decouple contact performance from threshold voltage influence even in narrow structures.
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
This design effectively reduces the influence on threshold voltage and suppresses latch-ups, even in miniaturized semiconductor devices, by ensuring efficient hole extraction and reducing ON voltage.
Implementation Method 1
This design effectively reduces the influence on threshold voltage and suppresses latch-ups, even in miniaturized semiconductor devices, by ensuring efficient hole extraction and reducing ON voltage
Data Source
AI summary
A semiconductor device having a contact trench is provided. The semiconductor device including: a semiconductor substrate; a drift region of the first conductivity type provided on an upper surface side of the semiconductor substrate; a base region of the second conductivity type provided above the drift region; a source region of the first conductivity type provided above the base region; two or more trench portions provided penetrating through the source region and the base region from an upper end side of the source region; a contact trench provided in direct contact with the source region between adjacent trench portions; and a contact layer of the second conductivity type provided below the contact trench, is provided. A peak of a doping concentration of the contact layer is positioned shallower than a position of a lower end of the source region.