ISFET using PbTiO3 as sensing film
AssigneeNational Yunlin University of Science and Technology
InventorsJung-Chuan Chou, Wen Liu, Wen Hong
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Abstract
A PbTiO3/SiO2-gated ISFET device comprising a PbTiO3 thin film as H+-sensing film, and a method of forming the same. The PbTiO3 thin film is formed through a sol-gel process which offers many advantages, such as, low processing temperature, easy control of the composition of the film and easy coating over a large substrate. The PbTiO3/SiO2 gated ISFET device of the present invention is highly sensitive in aqueous solution, and particularly in acidic aqueous solution. The sensitivity of the present ISFET ranges from 50 to 58 mV/pH. In addition, the disclosed ISFET has high linearity. Accordingly, the disclosed ISFET can be used to detect effluent.
Claims16
1-11. (canceled)
A method of forming a sensing film, comprising the steps of:
- forming a solution of lead acetate hydrate and 1,3-propanediol in a molar ratio of 1:5 in a solvent;
- heating the solution and cooling the solution to form powder;
- adding titanium diisopropoxide in a molar ratio of 1:1 to the powder to form a mixture and heating the mixture, and cooling the mixture, thereby achieving the homogeneity of the mixture;
- refluxing the mixture and cooling the mixture;
- and
- forming the mixture into a film on a surface and performing a pyrosol process on the film to form a PbTiO3 thin film.
A method of making a PbTiO3/SiO2-gated ISFET device, comprising the steps of:
- providing a semiconductor substrate with a gate oxide layer thereon, and a pair of source/drain regions formed in the semiconductor substrate oppositely adjacent to the gate oxide layer;
- forming a gel into a film overlying the gate oxide layer and performing a pyrosol process on the film to form a PbTiO3 layer as a PbTiO3 gate, wherein the gel is obtained by the steps of:
- forming a solution of lead acetate hydrate and 1,3-propanediol in a molar ratio of 1:5 in a solvent;
- heating the solution and cooling the solution down to form powder;
- adding titanium diisopropoxide in a molar ratio of 1:1 to the powder to form a mixture and heating the mixture, and cooling the mixture, thereby achieving the homogeneity of the mixture;
- and
- refluxing the mixture and cooling the mixture to form the gel;
- connecting metal wires on the source/drain regions;
- and
- forming a sealing layer overlying the metal wire to seal the device but leave the PbTiO3 gate exposed.
Dependencies are inferred from the claim text.