Four point semiconductor nanowire-based sensors and related methods
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Publication Number
US-11579114-B2
Publication Date
2023-02-14
Expiration Date
Abstract
The techniques relate to methods and apparatus for sensing an analyte. At least one sensor element is configured to sense an analyte, the at least one sensor element comprising a first portion and a second portion. A first current electrode is attached to the first portion and a second current electrode is attached to the second portion. A first measurement electrode is attached to the first portion and a second measurement electrode is attached to the second portion.
Core Innovation
The invention relates to semiconductor nanowire-based sensors and nanochannel-based sensing elements configured to sense an analyte using separated electrodes for reduced electrical noise. It emphasizes a four-point measurement scheme where current electrodes and measurement electrodes are separated, and a voltage measurement is intended to reflect mainly the functionalized sensor region rather than electrode-related noise or background.
A key aspect is ion-implanted metal-to-semiconductor contact pad structures, in which contact pads have portions that overlap the source and drain of a semiconductor sensor. The described configuration provides low-resistance ohmic contacts by using ion-implanted portions for the electrode connection to the semiconductor source and drain, while other portions of the contact pads are not ion-implanted.
The disclosed approach additionally includes integrated on-chip fluid conductance and ionic concentration measurement to interpret biosensor signals and reduce false positives/false negatives caused by ionic background effects, including Debye length effects. The document describes using two- or four-electrode configurations for fluid conductance sensing and optionally AC versus DC measurement, including electrode arrays and field adjustment electrodes, to support interpretation of the biosensor response.
Claims Coverage
Independent claim clm-00001 covers a device that integrates a semiconductor sensor for analyte sensing with separated current and measurement electrodes connected through contact pads whose overlapping portions with the source and drain differ by ion implantation. The main inventive features across the independent claim are structured around the four-point electrode separation and ion-implanted versus non-ion-implanted contact-pad portions overlapping the source and drain.
Four-point electrode separation to sense an analyte
A device includes at least one sensor element configured to sense an analyte, where first and second current electrodes are attached to first and second contact pads, and first and second measurement electrodes are also attached to the contact pads so that current and voltage (measurement) electrodes are separated.
Contact pads with portions overlapping the source and drain
The first contact pad is in electrical communication with the source and comprises a first portion and a second portion different from the first portion, where the first portion overlaps the source; the second contact pad is in electrical communication with the drain and comprises a first portion and a second portion different from the first portion, where the first portion overlaps the drain.
Ion-implanted overlapping contact-pad portions
The first portions of the contact pads are ion-implanted and the second portions are not ion-implanted.
Overall, clm-00001 centers on a four-point electrode architecture for analyte sensing with the measurement electrodes connected via contact pads having source- and drain-overlapping portions. It further requires ion-implanted overlapping portions to form the low-resistance contact, while non-ion-implanted portions are defined separately.
Stated Advantages
Reduced electrical noise and reduced electrical noise/background in the measurement by separating current electrodes from measurement electrodes in a four-point measurement scheme.
Measured voltage is intended to reflect mainly the functionalized sensor region rather than electrode-related artifacts.
Integration of fluid conductance/ionic concentration measurement is intended to reduce false positives/false negatives due to ionic background effects, including Debye length effects.
Documented Applications
Analyte sensing using semiconductor nanowire-based sensors and nanochannel-based sensing elements configured for biosensor operation with separated current and measurement electrodes.
Interpreting biosensor signals by measuring fluid conductance/ionic concentration on-chip (using two- or four-electrode configurations and optionally AC/DC measurement) to address ionic background effects such as Debye length effects.
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