MOSFET Source Resistance Control Region Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices, such as MOSFETs, face a trade-off between short-circuit resistance and on-resistance, with increasing short-circuit resistance leading to higher on-resistance, and current solutions like adjusting source resistance control region length or impurity concentration either reduce throughput or increase on-resistance.
Innovation Solution
A semiconductor device configuration with a source region comprising a low concentration source resistance control region and a high concentration source resistance control region, where the high concentration region is formed between the low concentration region and the well region, effectively suppressing depletion layer extension and maintaining low on-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the source resistance control region is designed with high resistance by increasing its length or reducing impurity concentration, then short-circuit resistance is enhanced, but on-resistance increases excessively
Solution Approach 1:
The source resistance control region is divided into two distinct zones: a first region with higher impurity concentration and a second region with lower impurity concentration. This local differentiation allows the first region to provide low resistance for normal operation while the second region contributes to voltage drop during short-circuit conditions, thereby enhancing short-circuit resistance without excessively increasing overall on-resistance.
Solution Approach 2:
The invention changes the impurity concentration parameter along the current flow direction in the source resistance control region. By creating a gradient or stepped distribution of impurity concentration (higher in the first region, lower in the second region), the device optimizes the balance between on-resistance and short-circuit resistance. This parameter variation allows different sections to serve different functional purposes.
2Reliability
If the impurity concentration of the source resistance control region is reduced to increase voltage drop, then short-circuit resistance improves, but depletion layer expansion increases on-resistance
Solution Approach 1:
The source resistance control region employs local quality differentiation with a first region having higher impurity concentration and a second region having lower impurity concentration. The higher concentration first region acts as a buffer that limits depletion layer penetration from the p-n junction, while the lower concentration second region provides the necessary voltage drop for short-circuit protection.
Solution Approach 2:
The first region with higher impurity concentration serves as an intermediary zone between the p-n junction and the second region. It mediates the depletion layer expansion by providing a transition zone with moderate doping, thereby preventing excessive depletion layer penetration into the low-concentration second region while still allowing sufficient voltage drop development.
3Reliability
If the length of the source resistance control region is increased to enhance voltage drop, then short-circuit resistance is improved, but manufacturing precision requirements increase
Solution Approach 1:
Instead of uniformly increasing the length of the source resistance control region, the invention applies local quality differentiation by creating two regions with different impurity concentrations within the available space. This allows effective short-circuit resistance enhancement through concentrated doping variations rather than extended geometric dimensions, thereby reducing manufacturing precision requirements for length control.
Solution Approach 2:
The invention substitutes geometric parameter changes (increasing length) with material parameter changes (varying impurity concentration). By controlling the doping concentration distribution rather than relying on precise dimensional control, the device achieves the desired voltage drop and short-circuit resistance with more manufacturable tolerances.
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 short-circuit resistance while keeping on-resistance low, improving the trade-off between the two and reducing manufacturing complexity.
Implementation Method 1
a depletion layer formed by a p-n junction between a well region and the source resistance control region
Implementation Method 2
a voltage drop caused by a current flowing in the source resistance control region becomes large then load short-circuit occurs and a saturation current value decreases
Data Source
AI summary
A source region of a MOSFET includes a source contact region connected to a source electrode, a source extension region adjacent to a channel region of a well region, and a source resistance control region provided between the source extension region and the source contact region. The source resistance control region includes a low concentration source resistance control region which has an impurity concentration lower than that of the source contact region or the source extension region and a high concentration source resistance control region which is formed between the well region and the low concentration source resistance control region and has an impurity concentration higher than that of the low concentration source resistance control region.