Vertical Trench MOSFET Structure for Low RON and Short-Circuit Limiting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vertical trench MOSFETs face a design challenge in balancing low on-resistance and low short-circuit current, which is crucial for efficient power electronics applications.
Innovation Solution
The implementation of p shielding implantations in every second trench of a vertical field effect transistor structure, along with deeper p body connections extending into the n− drift zone, creates a PN transition that reduces resistance at high drain voltages and limits short-circuit current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If p shielding implantations are implemented in every second trench, then short-circuit current is limited, but on-resistance increases
Solution Approach 1:
The patent applies p shielding implantations selectively in every second trench rather than uniformly in all trenches. This local differentiation creates alternating patterns of shielded and unshielded trenches, allowing the structure to limit short-circuit current through the shielded trenches while maintaining lower on-resistance through the unshielded trenches, thus resolving the contradiction between these two parameters.
2Reliability
If deeper p body connections are implemented, then resistance at high drain voltages is reduced, but device complexity increases
Solution Approach 1:
The patent implements deeper p body connections that extend into the n- drift zone before the trench structures are fully formed. This preliminary action of extending p body connections deeper into the drift zone beforehand allows the structure to naturally reduce resistance at high drain voltages through the formed PN transition, while avoiding the need for additional complex processing steps that would increase device complexity.
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 approach effectively reduces the specific on-resistance and limits short-circuit current, enhancing the overall performance and reliability of the vertical field effect transistor structure for power electronics.
Implementation Method 1
The p-doped zone and the drift zone or the drain zone form a diode... a PN transition is thus created below the channel and reduces the resistance at high drain voltages
Implementation Method 2
A JFET is thus formed at the p-doped zones and serves to limit the current through the channel region in the event of a short circuit... the space charge zones emanating from the p-doped zone approach one another such that a pinch off of the short-circuit current occurs
Data Source
AI summary
A method for manufacturing a vertical field effect transistor structure and a vertical field effect transistor structure. The vertical field effect transistor structure has a semiconductor body having first and second connection zones of a first conductor type, a channel zone of the first conductor type, or of a second conductor type complementary to the first conductor type, arranged between the first and second connection zone, a plurality of trenches extending into the semiconductor body, the trenches reaching from the second connection zone through the channel zone into the first connection zone and forming fins of the channel zone and of the second connection zone, a control electrode arranged in the trenches, the electrode being arranged adjacent to the channel zone and insulated from the semiconductor body, and a breakdown current path connected between the first and second connection zones and in parallel with the channel zone.