KR100964202B1 - FET-type Biosensor using titanum thin layer and method thereof - Google Patents

Abstract

The present invention relates to a FET type biosensor using a titanium film. The FET biosensor includes a reference signal element and a sensor element formed on the same semiconductor substrate, and the reference signal element includes a source, a drain, a gate insulating film, a polycrystalline silicon layer, a first metal layer, and a second metal layer formed on the semiconductor substrate. A metal layer, and the sensor element comprises a source, a drain, a gate insulating film, a semiconductor thin film, a fourth metal layer, a third metal layer. The second metal layer is formed on the first metal layer so that the self-assembled monolayer is not formed thereon, and the third metal layer is formed on the fourth metal layer so that the self-assembled monolayer is formed thereon. The first metal layer of the reference signal element and the fourth metal layer of the sensor element are made of a titanium thin film, the second metal layer is made of a platinum (Pt) thin film, and the third metal layer is made of gold (Au).

Biosensor, sensor element, reference signal element, titanium

Description

FET type biosensor using titanium thin film and its manufacturing method {FET-type Biosensor using titanum thin layer and method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a FET type biosensor that detects the concentration or detects the presence of specific biomolecules using the principle of a field effect transistor. The present invention relates to a FET-type biosensor which prevents the polycrystalline silicon layer from being excessively exposed during the process of manufacturing a reference signal element and a sensor element by forming a titanium thin film.

Biosensor is a sensor that can quickly quantify the concentration of various bioactive substances by using the intermolecular selective reactivity of the biomaterial only, the first application of biochip technology to induce electrical signals from various biochemical reactions. In particular, as the DNA sequence of human beings is known due to the completion of the genome project, the research on the function of each gene and the proteins encoded by them becomes more active, and the necessity for a biosensor capable of easily detecting biomaterials increases. have. Biosensors capable of detecting biomaterials using electrical signals are disclosed in US Pat. Nos. 4,328,757, 4,777,019, 5,431,883, and 5,827,482.

US Pat. No. 4,238,757 discloses a FET designed to have an antigen that reacts to a particular antibody, and the FET is used to measure the concentration of antigen in solution by observing the change in drain current over time.

U. S. Patent No. 4,777, 019 discloses a FET having a source, a drain region and a gate region, in which a nucleotide complementary to the nucleotide to be measured is bound on the gate, and in particular in place of the gate metal, the biological monomers ) Is disclosed to measure the degree of hybridization with complementary monomers by adsorption on the surface of the gate by FET.

U.S. Patent No. 5,431,883 discloses a FET having a structure in which a thin film of phthalocyanine, an organic insulating material having a property of reacting with a chemical specimen and converting into a conductivity, is connected to a gate and a drain.

Korean Patent No. 10-0244001 discloses a conductive polymer thin film in a FET-type biosensor with a gate metal (gold or aluminum, etc.) and a polymer material capable of recognizing pathogens in the form of multiple thin films on the top of the thin film. Disclosed is a biosensor for measuring.

Korean Unexamined Patent Publication No. 10-2005-0039418 discloses a technique of adsorbing a protein onto a self-assembled monolayer on the surface of a gate metal in a FET-type biosensor having a gate metal (Au, etc.).

Korean Patent No. 10-0938081 discloses that an inorganic film may be selectively deposited only on a gate surface of an FET in a FET type biosensor having a gate metal (Au, etc.) or an inorganic film may be selectively deposited only on a part of gate surfaces of a plurality of FETs. A FET-based biosensor is disclosed.

As described above, various types of FET-type biosensors are manufactured by using a semiconductor process, and have advantages of fast electrical signal conversion and easy integration with IC.

However, FET type biosensors have a problem of low signal-to-noise ratio (S / N ratio). Various efforts are being made to solve this problem. One method is to form a reference signal transistor together with a biosensor transistor. In this case, the biosensor transistor mainly uses Au as a sensing film, but the reference signal transistor uses a metal layer, for example, a platinum thin film, which is different from the sensing film of the biosensor transistor.

In this case, in order to manufacture one biosensor, a sensing film of the biosensor transistor and a sensing signal of the reference signal transistor should be formed. Therefore, in order to form various kinds of metal sensing films, it is necessary to repeatedly perform as many types of sensing films as metals to be deposited / etched or lift off. In this case, a defect including more contamination occurs on the surface of the metal sensing film when the first metal film is formed on the metal sensing film and the gate insulating layer or on the polycrystalline silicon layer of the gate.

An object of the present invention for solving the above problems is to provide a FET-type biosensor that improves the performance and reliability of the device by minimizing the defect of the metal-sense layer in the FET-type biosensor that requires a multi-metal sensing film.

Another object of the present invention is to provide a FET type biosensor that can simplify the manufacturing process using a titanium film.

In the FET type biosensor comprising a reference signal element and a sensor element formed on the same semiconductor substrate according to the first aspect of the present invention,
The reference signal element may include a source and a drain for a reference signal element formed on the semiconductor substrate; A gate insulating film for reference signal elements formed on the semiconductor substrate; A semiconductor thin film for reference signal elements formed on the gate insulating film for reference signal elements; A first metal layer formed on the semiconductor thin film for the reference signal element; And a second metal layer formed on the first metal layer so that the self-assembled monolayer is not formed thereon.
The sensor element may include a source and a drain for a sensor element formed on the semiconductor substrate; A gate insulating film for sensor elements formed on the semiconductor substrate; A semiconductor thin film for sensor elements formed on the gate insulating film for sensor elements; A fourth metal layer formed on the sensor thin film for semiconductor; And a third metal layer formed on the fourth metal layer in order to form a self-assembled monolayer on the upper side.
The first metal layer of the reference signal element and the fourth metal layer of the sensor element are made of a titanium thin film, the second metal layer is made of a platinum (Pt) thin film, and the third metal layer is made of gold (Au).

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

A FET type biosensor manufacturing method for manufacturing a reference signal element and a sensor element on a semiconductor substrate according to a second aspect of the present invention,

(a) forming a source and a drain in the regions where the device is to be formed on the semiconductor substrate;

(b) sequentially forming a gate insulating film, a semiconductor thin film, and a first metal layer between each source and drain;

(c) forming a second metal layer over the first metal layer in the region where the element for reference signal is to be formed;

(d) forming a third metal layer over the first metal layer in the region where the sensor element is to be formed;

The first metal layer is made of a titanium thin film, the second metal layer is made of a platinum thin film, and the third metal layer is made of a gold (Au) thin film.

The FET type biosensor according to the present invention forms a titanium film on the polycrystalline silicon film, thereby preventing the polycrystalline silicon film from being exposed to the air several times in the manufacturing process to form the metal sensing film even when a multiple metal sensing film is required. The occurrence of gate defects in the metal sensing film formed on the polycrystalline silicon film can also be reduced. Therefore, it is possible to improve the overall performance and reliability of the biosensor.

In addition, according to the present invention, the titanium film can be used as a metal film for improving adhesion between the platinum film, which is the uppermost metal layer of the reference signal sensor, and the polycrystalline silicon film, thereby simplifying the manufacturing process.

Hereinafter, the configuration of the FET-type biosensor according to a preferred embodiment of the present invention and a manufacturing method thereof will be described in detail with reference to FIG. 1.

1 is a cross-sectional view of a FET type biosensor according to a preferred embodiment of the present invention. Referring to FIG. 1, in the FET-type biosensor 10 according to the present invention, a reference signal element 20 and a sensor element 30 are formed on a single semiconductor substrate, and the reference signal element 20 is a semiconductor substrate. And a source 210 and a drain 212, a gate insulating film 220, a polycrystalline silicon film 230, a first metal layer 240, and a second metal layer 250 formed on the substrate 100. 30 includes a source 310 and a drain 312, a gate insulating film 320, a polycrystalline silicon film 330, a first metal layer 340, and a third metal layer 350 formed on the semiconductor substrate 100.

Since the semiconductor substrate, the source, the drain, the gate insulating film, and the polycrystalline silicon film of the reference signal element and the sensor element are the same as those of a general field effect transistor, they are well known in the art and detailed description thereof will be omitted.

The second metal layer 250 of the reference signal device is a top metal layer, and is preferably made of a platinum (Pt) thin film so that a self-assembled monolayer is not formed. In addition, the third metal layer 350 of the sensor element is also made of gold (Au) to facilitate the formation of a self-assembled monolayer as a top metal layer. The second metal layer and the third metal layer are uppermost metal layers and are exposed to the outside.

The first metal layer 240 is formed between the second metal layer and the polycrystalline silicon film and between the third metal layer and the polycrystalline silicon film, and is made of a titanium film. By forming the first metal layer with a titanium film, adhesion between the surface of a semiconductor thin film such as polycrystalline silicon and metals used as a sensing film is improved, thereby providing long-term stability of the metal positioned at the top of the biosensor.

In forming the titanium film of the reference signal device, the titanium film may be used as the adhesion-improving metal without depositing an additional adhesion-improving metal to improve the adhesion, thereby simplifying the entire process. do.

In addition, by forming a first metal layer made of titanium on the polycrystalline silicon layer of the biosensor according to the present invention, the polycrystalline silicon layer or the exposed gate insulating film for forming the multi-metal sensing film in a process requiring a multi-metal sensing film. This prevents exposure to the atmosphere during several processes. As a result, contamination caused by exposure of the gate insulating film or the polycrystalline silicon layer and defects of the sensing film formed thereon can be reduced.

Hereinafter, a FET type biosensor manufacturing method including a reference signal element and a sensor element on one semiconductor substrate having the above-described configuration will be described.

After the source and the drain are respectively formed in the regions where the reference signal element and the sensor element are to be formed on the semiconductor substrate, a gate insulating film, a semiconductor thin film, and a first metal layer are sequentially formed between each source and drain.

Next, a second metal layer is formed on the first metal layer in the region where the element for reference signal is to be formed. In this case, in order to form the second metal layer, the second metal layer is completed by depositing platinum (Pt) on the first metal layer, and then etching an area except the region where the reference signal element is to be formed.

Next, a third metal layer is formed on the first metal layer in the region where the sensor element is to be formed. At this time, in order to form the third metal layer, gold (Au) forming the third metal layer is deposited on the first metal layer, and then the region except for the region where the sensor element is to be formed is etched to complete the third metal layer.

 At this time, the first metal layer is made of a titanium thin film, the second metal layer is made of a platinum thin film, and the third metal layer is made of a gold (Au) thin film.

Although the present invention has been described above with reference to preferred embodiments thereof, this is merely an example and is not intended to limit the present invention, and those skilled in the art do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications which are not illustrated above in the scope are possible. And differences relating to such modifications and applications should be construed as being included in the scope of the invention as defined in the appended claims.

The technique according to the invention can be widely used in the field of biosensors.

1 is a cross-sectional view showing a FET-type biosensor according to a preferred embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10: FET type biosensor (10)

20: element for reference signal

30 sensor element

100: semiconductor substrate

210, 310: Source

212, 312: drain

220, 320: gate insulating film

230, 330 polycrystalline silicon film

240 and 340: first metal layer

250: second metal layer

350: third metal layer

Claims (4)

In the FET type biosensor comprising a reference signal element and a sensor element formed on the same semiconductor substrate, The reference signal element A source for a reference signal element and a drain for a reference signal element formed on the semiconductor substrate; A gate insulating film for reference signal elements formed on the semiconductor substrate; A semiconductor thin film for reference signal elements formed on the gate insulating film for reference signal elements; A first metal layer formed on the semiconductor thin film for the reference signal element; And a second metal layer formed on the first metal layer so that the self-assembled monolayer is not formed thereon. The sensor element is A sensor element source and a sensor element drain formed on the semiconductor substrate; A gate insulating film for sensor elements formed on the semiconductor substrate; A semiconductor thin film for sensor elements formed on the gate insulating film for sensor elements; A fourth metal layer formed on the sensor thin film for semiconductor; And a third metal layer formed on the fourth metal layer in order to form a self-assembled monolayer on the upper side. FET type biosensor, characterized in that the first metal layer of the reference signal element and the fourth metal layer of the sensor element are made of a titanium thin film. The FET type biosensor according to claim 1, wherein the second metal layer is made of a thin film of platinum (Pt). The FET type biosensor according to claim 1, wherein the third metal layer is made of gold (Au). In the FET type biosensor manufacturing method for manufacturing a reference signal element and a sensor element on one semiconductor substrate, (a) forming a source and a drain in the regions where the device is to be formed on the semiconductor substrate; (b) sequentially forming a gate insulating film, a semiconductor thin film, and a first metal layer between each source and drain; (c) forming a second metal layer over the first metal layer in the region where the element for reference signal is to be formed; (d) forming a third metal layer over the first metal layer in the region where the sensor element is to be formed; And a first metal layer made of a titanium thin film, a second metal layer made of a platinum thin film, and a third metal layer made of a gold (Au) thin film.

Images