Trench-Filled Semiconductor Device Reducing Parasitic Resistance
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Solution Overview
Problem
In vertical semiconductor devices, parasitic resistance between the sides of the device is detrimental due to high current densities, especially in low-voltage FETs with thin drift zones, necessitating a reduction in on-state resistance.
Innovation Solution
A semiconductor device with a trench extending into the substrate from one side, capped by a semiconductor layer, and a contact on the opposite side, which includes a conductive material and a diffusion barrier to minimize parasitic resistance, and a method of manufacturing involving trench formation, conductive filling, and semiconductor layer deposition to enhance conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thin wafer techniques are used to reduce drift zone thickness in low-voltage devices, then voltage blocking capability is improved, but parasitic resistance increases
Solution Approach 1:
The substrate is segmented by introducing trenches that divide the continuous substrate into regions. These trenches are filled with conductive material to create low-resistance pathways, effectively segmenting the current flow paths to reduce overall parasitic resistance while maintaining the thin drift zone structure for voltage blocking
Solution Approach 2:
Different regions of the substrate are given different properties: the drift zone maintains thin thickness for voltage blocking, while trench regions are filled with highly conductive materials to provide low-resistance current paths. This local differentiation allows simultaneous optimization of both voltage blocking capability and parasitic resistance reduction
2Object-affected harmful factors
If conductive material is added to reduce parasitic resistance, then conductivity is improved, but device complexity increases
Solution Approach 1:
The conductive material is nested within the trench structures that are already part of the device architecture. The trenches themselves are formed as part of the standard device fabrication process, and the conductive filling utilizes this existing structural framework, thereby reducing the incremental complexity added by the resistance reduction measure
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 effectively reduces on-state resistance and improves conductivity, addressing the issue of parasitic resistance and enhancing the performance of vertical semiconductor devices.
Implementation Method 1
a first trench extending into or through the semiconductor substrate from a first side... a conductive material and a diffusion barrier
Implementation Method 2
a semiconductor layer adjoining the semiconductor substrate at the first side, wherein the semiconductor layer caps the first trench at the first side
Data Source
AI summary
A semiconductor device includes a semiconductor substrate and a first trench extending into or through the semiconductor substrate from a first side. The first trench is at least partially filled with a conductive material and electrically connected to the semiconductor substrate via a doped semiconductor layer at a sidewall of the first trench. A semiconductor layer adjoins the semiconductor substrate at the first side, and caps the first trench at the first side. A contact is disposed at a second side of the semiconductor substrate opposite to the first side. A method of manufacturing the semiconductor device is also provided.