Lateral Super Junction JFET Layout for Drain Field Shaping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices with alternating n- and p-layers face challenges in achieving uniform electric field distribution and high breakdown voltage due to localized electric field increases near the drain, leading to premature electric breakdown.
Innovation Solution
A semiconductor device with a lowermost layer of alternating conductivity type arranged in consecutive dots of varying lengths and distances within deep polycrystalline trenches, reducing the electric field near the drain and achieving a more uniform electric field distribution by modifying the layer structure and trench configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a uniform stack of alternating n- and p-layers is used, then optimal material utilization for breakdown voltage is achieved, but the electric field concentrates near the drain causing premature breakdown
Solution Approach 1:
The lowermost layer is segmented into consecutive dots of alternating conductivity types with varying lengths and distances, rather than using a uniform continuous layer. This segmentation creates a non-uniform charge distribution that shapes the electric field to be more uniform across the drift region, preventing field concentration near the drain and enabling higher breakdown voltage
Solution Approach 2:
The patent applies local quality by varying the lengths and distances of the dotted layers in different regions. The lowermost layer has dots with different dimensions and spacing compared to upper layers, creating locally optimized charge distribution that shapes the electric field profile to maintain uniformity throughout the drift region while maximizing breakdown voltage
2Device complexity
If the bottom channel is abruptly ended at the drain, then device structure is simplified, but the electric field must turn 90 degrees vertically in the substrate creating a U-shape profile with highest field near drain
Solution Approach 1:
The abrupt channel termination is replaced with a segmented dotted layer structure that gradually transitions the electric field. The consecutive dots with varying lengths and distances create a progressive field shaping effect that prevents the sharp 90-degree field turn and U-shape profile, reducing peak field concentration near the drain
Solution Approach 2:
The patent introduces a new dimensional approach by using dots with varying lengths in the lateral direction and varying distances in the vertical direction. This multi-dimensional variation in the lowermost layer creates a three-dimensional charge distribution that shapes the electric field profile more effectively than simple abrupt termination
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 configuration enhances breakdown voltage and current flow by reducing the electric field near the drain, allowing for higher voltage handling and improved performance across different drain voltage levels.
Implementation Method 1
The stack of alternating n- and p-layers will, if they are matched in charge, completely deplete each other and a uniform electric field can be formed in the material
Implementation Method 2
a lowermost layer of the first conductivity type is arranged in the form of consecutive dots with different lengths and distances between deep polycrystalline trenches of the second conductivity type in the bottom part of the JFET
Data Source
AI summary
Disclosed is a semiconductor device, including: a substrate of a first conductivity type that is a base for the semiconductor device; a high voltage junction field effect transistor, JFET, over the substrate, wherein the JFET including a plurality of parallel conductive layers; and a first conductive layer of the second conductivity type of the parallel conductive layers stretching over the substrate. On top of the first conductive layer of the second conductivity type is arranged a plurality of layers forming the parallel conductive layers with channels formed by a plurality of doped epitaxial layers of the second conductivity type with a plurality of gate layers of the first conductivity type on both sides thereof; wherein a lowermost layer of the first conductivity type is arranged in the form of consecutive dots with different lengths and distances between them.