Chemical sensors, in particular silicon-based biosensors
First Claim
1. A chemical sensor which comprises:
- a body of silicon etched from an active surface thereof to form a pore network penetrating into said body from said active surface and forming a foam structure from said body at least along said surface;
a layer of at least one reactive material in said foam structure and lining pores thereof, whereby said layer can contact and react with an environment to alter conductivity characteristics of said body; and
at least one electrode in contact with a surface of said body opposite said active surface for electrical measurement of altered conductivity of said body, said pores having pore openings selected to enable said pores to accommodate said material.
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Accused Products
Abstract
A three-dimensional structure of porous silicon considerably improves the anchorage of sensor-active material such as, for example, enzymes, antibodies, etc., on or in the substrate surface of chemical sensors, in particular silicon-based biosensors. This structure is produced by means of suitable etching which forms pore apertures adapted to the penetrability of the sensor-active material. The pore walls advantageously receive a non-conductive boundary layer which consists of oxides of Si and/or Al or Ta or silicon nitride and are preferably 1-100 nm thick. The porous layer is advantageously between 10 nm and 100 μm thick and the pores are preferably in the form of branched ducts whose average diameter is 1 nm-10 μm and in particular 10-1000 nm. The sensor-active material can optionally be distributed in a glass, solid, plastics or polymer membrane.
62 Citations
11 Claims
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1. A chemical sensor which comprises:
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a body of silicon etched from an active surface thereof to form a pore network penetrating into said body from said active surface and forming a foam structure from said body at least along said surface; a layer of at least one reactive material in said foam structure and lining pores thereof, whereby said layer can contact and react with an environment to alter conductivity characteristics of said body; and at least one electrode in contact with a surface of said body opposite said active surface for electrical measurement of altered conductivity of said body, said pores having pore openings selected to enable said pores to accommodate said material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of making a chemical sensor which comprises the steps of:
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a) etching a body of silicon from an active surface thereof to form a pore network penetrating into said body from said active surface and forming a foam structure from said body at least along said surface with a thickness of 10 nm to 100 μ
m, said pore structure being constituted of branched pores having a mean pore diameter of 1 nm to 10 nm;b) lining said pores with a nonconducting boundary layer selected from the Group which consists of silicon dioxide, aluminum oxide, tantalum oxide, silicon nitride and mixtures thereof, said boundary layer having a thickness of 1 to 100 nm; c) depositing in said pores at least one reactive material in a layer which can contact and react with an environment to alter conductivity characteristics of said body; and d) applying to said body at least one electrode in contact with a surface of said body opposite said active surface for electrical measurement of altered conductivity of said body, said pores having pore openings selected to enable said pores to accommodate said material. - View Dependent Claims (11)
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Specification