Semiconductor Transistor Channel Width Optimization
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Solution Overview
Problem
Power transistors in automotive and industrial electronics require low on-state resistance (Ron) and high voltage blocking capability, with existing designs struggling to achieve optimal channel width and breakdown voltage characteristics.
Innovation Solution
A semiconductor device with a transistor structure featuring a channel region and drift zone, where the channel width is optimized to be less than or equal to twice the length of the depletion zone, and an auxiliary trench is used for doping the source region, enhancing the transistor's channel width and breakdown voltage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the channel width is increased to reduce on-state resistance, then the on-state resistance decreases, but the breakdown voltage capability deteriorates
Solution Approach 1:
The patent applies local quality by creating different doping concentrations in specific regions: the channel region has a first doping concentration while the drift zone has a second doping concentration. This localized differentiation allows the channel to support high current (low on-state resistance) while the drift zone maintains high breakdown voltage capability through optimized doping in that specific region.
Solution Approach 2:
The patent changes physical parameters by optimizing the channel width to be less than or equal to twice the depletion zone length, and by adjusting doping concentrations in different regions. These parameter changes enable simultaneous achievement of low on-state resistance and high breakdown voltage by tuning the electrical characteristics of specific zones independently.
2Productivity
If the channel width is increased to handle larger currents, then the current capacity increases, but the voltage blocking capability decreases
Solution Approach 1:
The patent segments the semiconductor structure into distinct functional zones: a channel region for current conduction and a drift zone for voltage blocking. This segmentation allows each region to be independently optimized - the channel width is increased for high current capacity while the drift zone is designed with appropriate doping and width for high breakdown voltage, resolving the contradiction between current handling and voltage blocking.
Solution Approach 2:
Different regions are assigned different doping concentrations and geometric dimensions tailored to their specific functions. The channel region has optimized doping and width for high current flow, while the drift zone has different doping characteristics for voltage blocking, allowing the device to simultaneously achieve high productivity and reliability.
3Ease of manufacture
If conventional doping methods are used, then the manufacturing process is simple, but the source region doping precision and efficiency are insufficient
Solution Approach 1:
The patent introduces an auxiliary trench as an intermediary structure to enable precise dopant introduction into the source region. This auxiliary trench serves as a controlled pathway that allows dopants to be introduced with higher precision while maintaining a relatively simple manufacturing process, as the trench can be formed using standard lithography and etching techniques followed by dopant diffusion or implantation.
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 results in reduced on-resistance, improved breakdown voltage characteristics, and increased robustness of power transistors, addressing the challenges of achieving high current densities and voltage blocking capabilities.
Implementation Method 1
The source region is formed using a doping method that introduces dopants via a sidewall of the auxiliary trench
Data Source
AI summary
A semiconductor device is formed by forming: a transistor in a semiconductor substrate having a main surface; a source region and a drain region; and a channel region and a drift zone between the source region and the drain region. The source and drain regions are arranged along a first direction parallel to the main surface. Gate trenches and a gate electrode are formed in the gate trenches. The gate trenches have a distance corresponding to a width d1 of the channel region, where d1≦2*ld and ld denotes a length of a depletion zone formed at an interface between the channel region and a gate dielectric adjacent to the gate electrode. An auxiliary trench formed in the main surface extends in a second direction intersecting the first direction. The source region is formed using a doping method that introduces dopants via a sidewall of the auxiliary trench.