Trench Transistor Gate-Drain Capacitance Reduction
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Solution Overview
Problem
Trench transistors face challenges in minimizing gate-drain capacitance, which leads to increased switching delays and losses, as existing methods do not effectively reduce the overlap between the gate electrode and the drift zone, thereby affecting the transistor's switching efficiency.
Innovation Solution
The method involves producing a trench transistor with a drift zone and a body zone by creating spacers on the trench sidewalls that leave a section of the trench bottom free, allowing for the introduction of dopant atoms to form a third semiconductor zone, which reduces the overlap and minimizes gate-drain capacitance by optimizing the positioning and doping of the semiconductor zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the gate electrode and drift zone overlap is reduced to minimize gate-drain capacitance, then switching losses are reduced, but the transistor's conducting capability and on-state current are degraded
Solution Approach 1:
The patent applies local quality by creating a highly doped drift zone section with different doping concentration than the surrounding drift zone. This localized doping enhancement allows the region directly beneath the gate electrode to maintain high conducting capability while the overall overlap is minimized, thus reducing gate-drain capacitance without sacrificing on-state current
Solution Approach 2:
The patent changes the doping parameter locally by introducing a highly doped drift zone section with doping concentration higher than the adjacent drift zone. This parameter change enables the region to serve dual functions: maintaining low gate-drain capacitance through reduced overlap while ensuring sufficient conducting capability through enhanced doping
2Loss of energy
If the trench depth is increased to reduce gate-drain capacitance, then switching performance is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent applies partial action by creating a highly doped drift zone section only in the region directly beneath the gate electrode, rather than doping the entire drift zone. This localized approach achieves the necessary capacitance reduction and conducting capability enhancement without requiring excessive trench depth or complex multi-layer structures throughout the entire device
3Reliability
If the doping concentration in the drift zone is increased to improve conducting capability, then on-state current is enhanced, but the gate-drain capacitance increases
Solution Approach 1:
The patent applies local quality by concentrating the high doping concentration specifically in the drift zone section beneath the gate electrode, rather than uniformly doping the entire drift zone. This localized high doping enhances conducting capability where needed for on-state current, while the reduced overlap geometry keeps the overall gate-drain capacitance low
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 results in a trench transistor with reduced gate-drain capacitance, enabling faster switching and lower switching losses by carefully controlling the overlap between the gate electrode and the drift zone, thus enhancing the transistor's performance.
Implementation Method 1
producing at least one third semiconductor zone of the first conduction type by introducing dopant atoms via the left-free section of the trench bottom
Data Source
AI summary
A method for producing an integrated circuit including a trench transistor and an integrated circuit is disclosed.