Semiconductor Bending Element Transistor Parasitic Stress Reduction
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Solution Overview
Problem
Micro-electromechanical semiconductor components used in pressure and acceleration sensors are often affected by parasitic influences and have high power consumption, making them unsuitable for energy-autonomous systems.
Innovation Solution
A micro-electromechanical semiconductor component with a reversibly deformable bending element and an integrated transistor designed to be insensitive to parasitic influences, featuring a doped semiconductor substrate, implanted drain and source regions, and polysilicon gate and feed lines, which maintains mechanical homogeneity and reduces oxygen layer thickness and thermal expansion issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional transistors with metallic feed lines and field oxide are used in the bending element, then electrical connectivity is achieved, but parasitic stress influences increase and measurement precision deteriorates
Solution Approach 1:
The patent removes metallic feed lines and field oxide structures from the bending element, extracting the sources of parasitic stress. Instead, insulated semiconductor feed lines are used that are integrated directly into the bending element structure, eliminating the harmful metallic components while maintaining electrical connectivity.
Solution Approach 2:
The patent changes the material parameters of the feed lines from metallic to semiconductor-based (heavily doped regions), and removes field oxide layers. This parameter change in material composition and structure eliminates the thermal expansion coefficient mismatches and stress issues associated with conventional metallic interconnects.
2Reliability
If the bending element contains multiple materials with different expansion coefficients (metallic feed lines, field oxide, gate oxide), then electrical functionality is achieved, but thermal expansion differences cause stress and reduce reliability
Solution Approach 1:
The patent creates a homogeneous material structure by using semiconductor material throughout the bending element, including for feed lines (heavily doped regions) and gate structures. This eliminates interfaces between materials with different thermal expansion coefficients, ensuring uniform thermal behavior and preventing stress accumulation during temperature changes.
Solution Approach 2:
The patent uses a composite semiconductor structure where the bending element, feed lines, and gate structures are all made of semiconductor material with different doping levels. This composite approach maintains material compatibility while achieving electrical functionality, avoiding the thermal expansion issues of heterogeneous material stacks.
3Measurement precision
If field oxide is applied on the bending element surface, then transistor isolation is achieved, but the bending element thickness becomes inhomogeneous causing stress field distortion
Solution Approach 1:
The patent removes field oxide layers from the bending element surface, extracting the source of thickness inhomogeneity. Transistor isolation is achieved through alternative means using the semiconductor structure itself (implanted regions and oxide layers only where absolutely necessary), maintaining bending element thickness uniformity and stress field homogeneity.
Solution Approach 2:
The patent applies oxide layers locally only where absolutely necessary for transistor operation, rather than using extensive field oxide coverage. This localized approach maintains the bending element's mechanical homogeneity in the regions critical for stress sensing while providing minimal oxide protection where electrical isolation is required.
4Use of energy by moving object
If conventional semiconductor manufacturing processes are used, then production capability is maintained, but power consumption is high making the system unsuitable for energy-autonomous applications
Solution Approach 1:
The patent uses heavily doped semiconductor regions instead of metallic interconnects, changing the electrical parameters to achieve lower resistance and power consumption. The semiconductor feed lines have sufficiently low resistance for energy-efficient operation while maintaining compatibility with standard CMOS manufacturing processes.
Solution Approach 2:
The patent replaces metallic electrical interconnects with semiconductor-based feed lines, substituting a different material system that provides both electrical functionality and mechanical compatibility. This substitution eliminates the need for complex multi-material processing while achieving ultra-low power operation suitable for energy-autonomous systems.
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 minimizes the impact of parasitic stress and reduces power consumption, enhancing the sensitivity and accuracy of the sensors while maintaining mechanical stability and low energy usage.
Implementation Method 1
an implanted active region pan that is made of a semiconductor material of a first conducting type and is introduced in the bending element... two mutually spaced, implanted drain and source regions made of a semiconductor material of a second conducting type
Implementation Method 2
Within these regions, the pan is strongly p+-doped. The entire pan (and optionally the region around the pan) is covered by a gate oxide
Implementation Method 3
a gate electrode made of polysilicon is located on the gate oxide in the area of the channel region, a feed line likewise made of polysilicon leading to said gate electrode
Implementation Method 4
a reversibly deformable bending element made of semiconductor material... which is reversibly deformable under the influence of forces acting from the outside
Implementation Method 5
the transistor is sensitive to mechanical stresses
Implementation Method 6
at least one transistor that is sensitive to mechanical stresses, said transistor being designed as an integrated component in the bending element
Data Source
AI summary
The micro-electromechanical semiconductor component is provided with a semiconductor substrate (4, 5), a reversibly deformable bending element (8a) made of semiconductor material, and at least one transistor that is sensitive to mechanical stresses, said transistor being designed as an integrated component in the bending element (8a). The transistor is arranged in an implanted active region pan (78a) that is made of a semiconductor material of a first conducting type and is introduced in the bending element (8a). Two mutually spaced, implanted drain and source regions (79, 80) made of a semiconductor material of a second conducting type are designed in the active region pan (78a), a channel region extending between said two regions. Implanted feed lines made of a semiconductor material of the second conducting type lead to the drain and source regions (79, 80). The upper face of the active region pan (78a) is covered by a gate oxide (81a). In the area of the channel region, a gate electrode (81) made of polysilicon is located on the gate oxide (81a), a feed line likewise made of polysilicon leading to said gate electrode.