Alternating Semiconductor Regions for High Impedance Biasing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor structures struggle to achieve high impedance values necessary for biasing miniature capacitive transducers like MEMS microphones, as conventional resistors and diodes require significant silicon area and suffer from noise attenuation and leakage issues.
Innovation Solution
A semiconductor structure with a continuous arrangement of alternating n-type and p-type regions, separated by intrinsic regions, forming a high impedance composite diode that provides increased saturation current and reduced parasitic capacitance, allowing for effective biasing of capacitive loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional resistors are used to bias MEMS transducers, then high impedance values can be achieved, but the silicon area required becomes excessively large
Solution Approach 1:
The patent divides a single high-value resistor into multiple lower-value resistor segments connected in series. Each segment has a manageable silicon area, and their combined resistance achieves the required high impedance. For example, instead of one 160 GΩ resistor requiring 16 mm², multiple smaller resistor segments are used to achieve the same total resistance with reduced individual area requirements.
Solution Approach 2:
The patent employs composite resistor structures combining different resistor types or configurations to achieve high impedance in compact areas. This may include series combinations of different resistor implementations or hybrid structures that leverage the advantages of multiple approaches to achieve both high resistance and small area.
2Reliability
If diodes are used to provide high resistance for biasing, then the resistance value increases, but leakage current and noise attenuation problems worsen
Solution Approach 1:
The patent segments the biasing function across multiple diode elements connected in series. Each diode contributes a portion of the total resistance, and the series connection multiplies the effect while reducing the burden on individual elements. This segmentation helps manage leakage current and noise by distributing the electrical stress and characteristics across multiple components rather than relying on a single high-value diode.
Solution Approach 2:
The patent introduces intermediate structures or elements between the diode and the transducer, such as additional resistive elements or buffering structures. These intermediaries help isolate the transducer from the harmful effects of diode leakage and noise, while still maintaining the high-impedance biasing function. The intermediary elements act as filters or isolators to reduce the impact of unwanted electrical characteristics.
3Area of stationary object
If resistor size is reduced to match transducer scale, then integration is improved, but the achievable resistance value decreases
Solution Approach 1:
The patent uses series connections of multiple small resistor segments to achieve high total resistance from small individual components. Each segment can be compact to match transducer scale, but their series combination produces the required high impedance value. This allows the overall structure to be integrated with miniature transducers while maintaining adequate biasing resistance.
Solution Approach 2:
The patent may employ three-dimensional resistor structures or multi-layer configurations to increase resistance density. By utilizing vertical stacking or layered arrangements, the effective resistance is increased without proportionally increasing the planar silicon area footprint, enabling high resistance values in compact integrated structures.
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 semiconductor structure achieves higher impedance values with reduced silicon area requirements and improved noise filtering, enabling effective biasing of MEMS transducers while minimizing parasitic capacitance and leakage issues.
Implementation Method 1
a continuous structure of semiconducting material comprising a plurality of regions of first semiconductor type, being n type or p type, and a plurality of regions of a second semiconductor type, being n type or p type and the opposite type to the first type, the regions of first semiconductor type and second semiconductor type being arranged alternately
Data Source
AI summary
Semiconductor structures with high impedances for use in biasing for applying voltage bias to part of a device. The semiconductor structure comprises a continuous structure having a plurality of regions of a first semiconductor type (n type or p type) material arranged alternately with at least one region of the opposite type. The structure may be formed from polysilicon and may also include a plurality of intrinsic regions arranged between the n and p type regions. The structure forms a composite diode and provides a high impedance.