CN105353000A - Semiconductor device and detection method thereof - Google Patents

Abstract

The invention relates to a semiconductor device and a detection method thereof. The semiconductor device comprises a semiconductor device used for capacitance detection and a dual-mode semiconductor device, wherein the semiconductor device used for capacitance detection eradicates influence of ionic activity through a first ion sensitive membrane and a second ion sensitive membrane which are identical so as to realize detection of the capacitance of a to-be-detected object, and the dual-mode semiconductor device is based on the semiconductor device used for capacitance detection and realized by applying a reference electrode on the semiconductor device used for capacitance detection and can realize detection of the capacitance and ionic activity of the to-be-detected object. In a preferable embodiment, a comb-shaped capacitor is introduced to allow work of the dual-mode semiconductor device to be more accurate. The semiconductor device with such a structure and the detection method thereof realize simultaneous detection of the capacitance and ionic activity of the to-be-detected object and improve measurement accuracy, which is beneficial for subsequent research on the to-be-detected object; and the device has a simple structure and a wide application scope.

Description

Semiconductor device and method for testing the same

Technical Field

The invention relates to the field of semiconductors, in particular to a semiconductor device, and specifically relates to a semiconductor device and a detection method thereof.

Background

The properties of the analyte have a direct influence on the physicochemical processes occurring therein, and particularly, for example, in the biological field, the ionic activity and dielectric properties of the electrolyte directly influence the biological processes therein, and also, for example, in the fields of petroleum, lubricating oil, and the like, the degree of cracking thereof has a great influence on the performance, durability, and energy saving of machines, devices, and the like using the petroleum, lubricating oil, and the like. There is therefore a need for a simple and accurate device and method for performing detection of a property of a liquid. In the prior art, a semiconductor device is generally used for detecting an object to be detected, and the method specifically includes the following steps:

first, fig. 1 is a schematic structural diagram of a semiconductor device for detecting ion activity in the prior art. The ion activity detection device comprises a semiconductor substrate B, a source S and a drain D, wherein the source S and the drain D are formed by doping on the substrate B, a grid insulation layer 5 is arranged on the substrate B, a grid electrode 4 is arranged on the grid insulation layer 5, an ion sensitive film 3 is arranged on the grid electrode 4, the ion sensitive film 3 is in contact with an object to be detected 2, a reference electrode 1 is inserted into the object to be detected 2, based on the structure, an equivalent circuit diagram of the ion activity detection device for detecting the ion activity in the object to be detected 2 is shown in figure 2, and the potential difference of the contact interface of the reference electrode 1 and the object to be detected 2 is psi_METhe electric potential of the electric double layer formed by the contact interface of the object 2 to be measured and the ion sensitive film 3 is V_EDLWherein said ion sensitive membrane 3 together with the electrolyte and the semiconductor part is equivalent to a first capacitor 6 and said electric double layer is equivalent to a fourth capacitor 10.

Although the prior art described above has achieved good results in various fields, the following problems still exist:

(1) the semiconductor device in the prior art only detects the ion activity of the substance to be detected, reflects too little information, cannot accurately describe the property of the substance to be detected, and is inconvenient for subsequent deep research;

(2) although the semiconductor device in the prior art also measures the capacitance of the object to be measured, the measurement method is complex, the accuracy and the repeatability need to be optimized, the cost is high, and the application range is limited.

Disclosure of Invention

The present invention is directed to overcome the above-mentioned drawbacks of the prior art, and provides a semiconductor device and a method for detecting the dielectric constant of an object to be detected, and simultaneously detecting the dielectric constant of the object to be detected and the ion activity of the object to be detected.

In order to achieve the above object, a semiconductor device and a method for testing the same according to the present invention includes:

the semiconductor device for capacitance detection comprises a substrate, a source electrode and a drain electrode, and is characterized by further comprising a capacitance detection part, wherein the capacitance detection part at least comprises a first ion sensitive film and a second ion sensitive film which is the same as the first ion sensitive film, an object to be detected is arranged between the first ion sensitive film and the second ion sensitive film, the first ion sensitive film is connected with the substrate, the second ion sensitive film is connected with the gate electrode, and the capacitance detection part is used for changing the capacitance at two ends of the capacitance detection part based on the filling of the object to be detected in the capacitance detection part, so that the threshold voltage of the semiconductor device is changed.

Furthermore, a gate insulating layer is arranged between the substrate and the first ion sensitive film, and a gate electrode is arranged between the gate insulating layer and the first ion sensitive film.

Furthermore, the gate electrode is a metal layer; or the gate electrode is a plurality of interconnected metal layers arranged in an insulating layer, and the plurality of interconnected metal layers are arranged between the gate insulating layer and the first ion sensitive film.

Further, the substrate on still be provided with the grid insulating layer, the grid insulating layer on be provided with the gate electrode, electric capacity detection portion still include the broach electric capacity, the broach electric capacity include first group broach electrode and second group broach electrode, first group broach electrode all with the gate electrode be connected, second group broach electrode all be connected with the gate power supply, first group broach electrode parcel have first ion sensitive membrane, second group broach electrode parcel have the second ion sensitive membrane, just broach electric capacity submergence in the determinand.

The invention also relates to a method for detecting the capacitance of the object to be detected, which is mainly characterized by comprising the following steps:

applying a constant first voltage between the gate power supply and the source, and a constant second voltage between the source and the drain of the semiconductor device; detecting the current flowing between the drain electrode and the source electrode to obtain the capacitance of the object to be detected;

or the method comprises the following steps:

and applying a constant third voltage between the gate power supply and the source electrode, applying a constant first current between the source electrode and the drain electrode of the semiconductor device, and detecting the voltage between the source electrode and the drain electrode of the semiconductor device to acquire the capacitance of the object to be detected.

The invention also relates to a dual-mode semiconductor device, which comprises a substrate, a source electrode and a drain electrode, wherein the source electrode and the drain electrode are arranged on the substrate, and the dual-mode semiconductor device is mainly characterized in that:

the dual-mode semiconductor device further comprises a capacitance detection part, wherein the capacitance detection part at least comprises a first ion sensitive film and a second ion sensitive film which is the same as the first ion sensitive film, an object to be detected is arranged between the first ion sensitive film and the second ion sensitive film, the first ion sensitive film is connected with the substrate, the second ion sensitive film is connected with a gate power supply, and the capacitance detection part is used for changing the capacitance at two ends of the capacitance detection part based on the filling of the object to be detected in the capacitance detection part, so that the threshold voltage of the dual-mode semiconductor device is changed;

and the reference electrode is inserted into the object to be tested and used for obtaining the ion activity of the object to be tested according to the change of the threshold voltage of the dual-mode semiconductor device.

Furthermore, a gate insulating layer is arranged between the substrate and the first ion sensitive film, and a gate electrode is arranged between the gate insulating layer and the first ion sensitive film.

Furthermore, the gate electrode is a metal layer; or the gate electrode is a plurality of interconnected metal layers arranged in an insulating layer, and the plurality of interconnected metal layers are arranged between the gate insulating layer and the first ion sensitive film.

Further, the substrate on still be provided with the grid insulating layer, the grid insulating layer on be provided with the gate electrode, electric capacity detection portion still include the broach electric capacity, the broach electric capacity include first group broach electrode and second group broach electrode, first group broach electrode all with the gate electrode be connected, second group broach electrode all be connected with the gate power supply, first group broach electrode parcel have first ion sensitive membrane, second group broach electrode parcel have the second ion sensitive membrane, just broach electric capacity submergence in the determinand.

The invention also relates to a method for simultaneously detecting the capacitance and the ionic activity of an object to be detected, which is mainly characterized by comprising the following steps of:

(a) detecting the capacitance of the object to be detected when the reference electrode is not inserted into the object to be detected or when the reference electrode inserted into the object to be detected is not electrified;

(b) and inserting the reference electrode into the object to be detected and electrifying the reference electrode to detect the ion activity of the object to be detected.

Further, the step (a) is specifically as follows:

applying a constant first voltage between a gate power supply and a source of said dual mode semiconductor device and a constant second voltage between a source and a drain of said dual mode semiconductor device; detecting the current flowing between the drain electrode and the source electrode to obtain the capacitance of the object to be detected;

or applying a constant third voltage between the gate power supply and the source of the dual-mode semiconductor device, applying a constant first current between the source and the drain of the dual-mode semiconductor device, and detecting the voltage between the source and the drain of the dual-mode semiconductor device to obtain the capacitance of the object to be measured.

Further, the step (b) is specifically as follows:

applying a constant fourth voltage to the reference electrode, applying a constant fifth voltage between the source and the drain, and detecting the current flowing between the drain and the source to obtain the ion activity of the analyte;

or applying a constant second current between the source and the drain of the dual-mode semiconductor device, applying a constant sixth voltage between the source and the reference electrode of the dual-mode semiconductor device, and detecting the voltage between the drain and the source of the dual-mode semiconductor device to obtain the ion activity of the analyte.

The semiconductor device for capacitance detection solves the problems that the detection of the electrolyte capacitance generally needs a complex driving circuit and a signal processing circuit, the cost is high and the application range is limited at present, and has simple structure and wide application range.

By adopting the dual-mode semiconductor device, the problem that the ion activity of the object to be detected is detected only through charge change in the prior art is solved, the accuracy of describing the property of the object to be detected is improved, the follow-up research is facilitated, and the dual-mode semiconductor device is simple in structure, high in accuracy and wide in application range.

Drawings

Fig. 1 is a schematic structural diagram of a semiconductor device for ion activity detection in the prior art.

Fig. 2 is an equivalent circuit diagram of fig. 1.

Fig. 3 is a schematic structural diagram of a semiconductor device for capacitance detection according to a first embodiment of the present invention.

Fig. 4 is an equivalent circuit diagram of fig. 3.

Fig. 5 is a schematic structural diagram of a semiconductor device for capacitance detection according to a second embodiment of the present invention.

Fig. 6 is an equivalent circuit diagram of fig. 5.

Fig. 7 is a schematic structural diagram of a more preferred embodiment of the second embodiment of the semiconductor device for capacitance detection according to the present invention.

Fig. 8 is a schematic structural diagram of a semiconductor device for capacitance detection according to a third embodiment of the present invention.

FIG. 9 is a diagram showing the change in potential at the contact interface between the analyte and the ion-sensitive membrane in the present invention.

FIG. 10 is a schematic view of the structure of a reference electrode of the present invention.

Fig. 11 is a schematic structural view of a dual-mode semiconductor device according to a first embodiment of the present invention.

Fig. 12 is a schematic structural view of a dual-mode semiconductor device according to a second embodiment of the present invention.

Fig. 13 is a schematic structural view of a dual-mode semiconductor device according to a third embodiment of the present invention.

Wherein,

1 reference electrode

1-1Ag core

1-2AgCl layer

1-3KCl saturated solution

2 test substance

3 ion sensitive membrane

31 first ion-sensitive membrane

32 second ion-sensitive membrane

4 gate electrode

5 Gate insulating layer

6 first capacitor

7 second capacitance

8 comb capacitor

9 third capacitance

10 fourth capacitance

11 metal layer

12 fifth capacitance

13 sixth capacitance

Detailed Description

In order to more clearly describe the technical contents of the present invention, the following further description is given in conjunction with specific embodiments.

Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of method steps and basic structures for determining properties of an analyte. Accordingly, the basic structures and method steps have been represented where appropriate by conventional symbols in the drawings, showing only those details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

In this document, relational terms such as left and right, top and bottom, front and back, first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

In order to solve the technical problem (2) in the background art, that is, the problems in the prior art that the device for detecting the capacitance of the object to be detected is complex, high in cost and low in detection accuracy, the invention provides a semiconductor device for capacitance detection.

First, referring to fig. 3, fig. 5 and fig. 7, fig. 3 is a schematic structural diagram of a semiconductor device for capacitance detection according to a first embodiment of the present invention, fig. 5 is a schematic structural diagram of a semiconductor device for capacitance detection according to a second embodiment of the present invention, and fig. 7 is a schematic structural diagram of a semiconductor device for capacitance detection according to a third embodiment of the present invention. The semiconductor device comprises a substrate B, a source S and a drain D which are arranged on the substrate B, wherein the semiconductor device also comprises a capacitance detection part, the capacitance detection part at least comprises a first ion sensitive film 31 and a second ion sensitive film 32 which is the same as the first ion sensitive film 31, an object to be detected 2 is arranged between the first ion sensitive film 31 and the second ion sensitive film 32, the first ion sensitive film 31 is connected with the substrate B, and the second ion sensitive film 32And a gate power supply V_GThe capacitance detection part is used for changing the capacitance at two ends of the capacitance detection part 2 based on the filling of the object 2 to be detected in the capacitance detection part, thereby the threshold voltage V of the semiconductor device_thAnd (6) changing. The semiconductor device for capacitance detection in the invention can obtain the capacitance of the object 2 to be detected without using the reference electrode 1, the dielectric constant of the capacitance detection part is changed due to the filling of the object 2 to be detected in the capacitance detection part, so that the capacitance of the capacitance detection part is changed, and the grid power supply V_GThe capacitance voltage division is changed under the condition of no change, and the threshold voltage V of the semiconductor device connected with the capacitance voltage division is changed_thAnd (6) changing.

Wherein, the first ion sensitive membrane 31 and the second ion sensitive membrane 32 are identical, no matter the material or the geometric dimension thereof; this is provided to avoid the influence of ion activity in the analyte 2 (for reasons described below), so that the capacitance of the analyte 2 can be accurately obtained.

The substrate B is a semiconductor substrate, and a source S and a drain D are formed on the semiconductor substrate in a doped mode; in a preferred embodiment, the semiconductor substrate is a P-type semiconductor, and the source S and the drain D are N-type semiconductors; in another preferred embodiment, the semiconductor substrate is an N-type semiconductor, and the source S and the drain D are P-type semiconductors.

In a preferred embodiment, the first ion-sensitive film 31 and the second ion-sensitive film 32 are single-layer insulating dielectric layers, and the material of the first ion-sensitive film 31 and the material of the second ion-sensitive film 32 are silicon dioxide SiO₂Silicon nitride Si₃N₄Al oxide AI₂O₃Or tantalum pentoxide Ta₂O₅. In another preferred embodiment, the first ion-sensitive film 31 and the second ion-sensitive film 32 are at least two insulating dielectric layers, and are connected to the semiconductor substrate or the semiconductor substrateThe layer contacted with the gate electrode on the conductor substrate is silicon dioxide SiO₂The most surface layer of the insulating medium layers, namely a layer at the joint of the insulating medium layers and the object to be detected, is silicon dioxide SiO₂Silicon nitride Si₃O₄Al oxide AI₂O₃Or tantalum pentoxide Ta₂O₅。

A: first embodiment of semiconductor device for capacitance detection of the present invention

Referring to fig. 3 and 4, fig. 3 is a schematic structural diagram of a semiconductor device for capacitance detection according to a first embodiment of the present invention, and fig. 4 is an equivalent circuit diagram of fig. 3. In a preferred embodiment, the semiconductor device includes a substrate B, a source S and a drain D disposed on the substrate, and a capacitance detection portion, the capacitance detection portion at least includes a first ion-sensitive film 31 and a second ion-sensitive film 32 identical to the first ion-sensitive film 31, an object 2 to be measured is disposed between the first ion-sensitive film 31 and the second ion-sensitive film 32, the first ion-sensitive film 31 is connected to the substrate B, and the second ion-sensitive film 32 is connected to a gate power supply V_GThe capacitance detection part is used for changing the capacitance at two ends of the capacitance detection part based on the filling of the object 2 to be measured in the capacitance detection part, thereby the threshold voltage V of the semiconductor device_thAnd (6) changing.

The second ion-sensitive film 32, the metal layer 11 connected to the second ion-sensitive film 32, and the electrolyte in the capacitance detection portion are equivalent to a third capacitor 9 in fig. 4, wherein the interfaces of the second ion-sensitive film 32 and the first ion-sensitive film 31 in contact with the object 2 form electric double layers, where the electric double layers are equivalent to a fifth capacitor 12 (the electric double layer formed by the interface of the first ion-sensitive film 31 in contact with the object 2) and a sixth capacitor 13 (the electric double layer formed by the interface of the second ion-sensitive film 32 in contact with the object 2) in fig. 4, respectively, so that the first end of the third capacitor 9 and the metal layer 11 connected to the second ion-sensitive film 32 can be obtained correspondinglyGrid power supply V_GIn connection with this, the second ion-sensitive membrane 32 can also be considered as a dielectric layer of the third capacitor 9.

In this embodiment, the first ion-sensitive film 31, the substrate B, the source S, the drain D, and the solution portion can be considered as a complete transistor, except that the gate insulating layer of the transistor is the first ion-sensitive film 31.

A1: second embodiment of semiconductor device for capacitance detection of the present invention

Referring to fig. 5 and fig. 6, wherein fig. 5 is a schematic structural diagram of a semiconductor device for capacitance detection according to a second embodiment of the present invention, and fig. 6 is an equivalent circuit diagram of fig. 5. The semiconductor device comprises a substrate B, a source S and a drain D which are arranged on the substrate, and further comprises a capacitance detection part, wherein the capacitance detection part comprises a first ion sensitive film 31 and a second ion sensitive film 32 which is the same as the first ion sensitive film 31, an object to be detected 2 is arranged between the first ion sensitive film 31 and the second ion sensitive film 32, the first ion sensitive film 31 is connected with a gate electrode 4, the gate electrode 4 is connected with a gate insulating layer 5, the gate insulating layer 5 is connected with the substrate B, and the second ion sensitive film 32 is connected with a gate source V through a metal layer 11_GAre connected.

Referring to fig. 5 in conjunction with fig. 6, the first ion-sensitive film 31 in fig. 5 is equivalent to a first capacitor 6 in fig. 6 together with the electrolyte and the gate electrode, and the second ion-sensitive film 32 in fig. 5 is equivalent to a second capacitor 7 in fig. 6 together with the metal layer 11 and the electrolyte; the second ion-sensitive film 32 and the interface of the first ion-sensitive film 31 contacting the object 2 form an electric double layer, where the two electric double layers are respectively equivalent to a fifth capacitor 12 (an electric double layer formed by the interface of the first ion-sensitive film 31 contacting the object 2) and a sixth capacitor 13 (an electric double layer formed by the interface of the second ion-sensitive film 32 contacting the object 2) in fig. 6, the first ion-sensitive film 31 can also be regarded as a dielectric layer of the first capacitor 6, and the second ion-sensitive film 32 can also be regarded as a dielectric layer of the second capacitor 7.

The semiconductor device for capacitance detection in the second embodiment can be regarded as one in which a gate electrode 4 and a gate insulating layer 5 are added, i.e., the first ion-sensitive film 31 is extended outward, in the semiconductor device for capacitance detection in the first embodiment.

Fig. 7 is a schematic structural diagram of a more preferred embodiment of a semiconductor device for capacitance detection according to a second embodiment of the present invention, wherein the gate electrode 4 is a metal layer; or the gate electrode 4 is a plurality of interconnected metal layers disposed in an insulating layer, and the plurality of interconnected metal layers are disposed between the gate insulating layer and the first ion sensitive film 31, in practical applications, generally, the gate electrode 4 is a plurality of interconnected metal layers disposed in an insulating layer, so as to improve stability of the device.

A2: third embodiment of the semiconductor device for capacitance detection of the present invention

Referring to fig. 8, a schematic structural diagram of a third embodiment of the semiconductor device for capacitance detection according to the present invention is shown, and an equivalent circuit thereof is shown in fig. 6, in this embodiment, a gate insulating layer 5 is further disposed on the substrate B, a gate electrode 4 is disposed on the gate insulating layer 5, the capacitance detection portion further includes a comb capacitor 8, the comb capacitor 8 includes a first group of comb electrodes and a second group of comb electrodes, the first group of comb electrodes are all connected to the gate electrode 4, and the second group of comb electrodes are all connected to the gate power source V_GAnd the first group of comb electrodes are wrapped with a first ion sensitive film 31, the second group of comb electrodes are wrapped with a second ion sensitive film 32, and the comb capacitor 8 is immersed in the object 2 to be detected.

The three embodiments described above are only three preferred embodiments of the semiconductor device for capacitance detection in the present invention, and it should not be understood that the present invention only includes the three embodiments described above, and therefore, it is within the scope of the present invention as long as it relates to a technical solution for eliminating the influence of the ion activity in the analyte 2 on the capacitance detection by two layers of the same ion sensitive film.

Meanwhile, it should be noted that since a change in the dielectric constant of the object 2 (typically, an electrolyte) causes a change in the capacitance of the object 2, the change in the dielectric constant of the object 2 is obtained by detecting the change in the capacitance of the object 2, and the dielectric constant of the object 2 is important for research in the fields of biology, petroleum, and the like, and therefore, the semiconductor device for capacitance detection of the present invention is intended to detect the change in the capacitance of the object.

While the following two specific modes are proposed in the present invention for detecting the change of the capacitance of the object 2, other changes can be made by those skilled in the art according to the needs and the semiconductor device for capacitance detection proposed in the present invention, and still fall within the protection scope of the present invention; the method for implementing the capacitance detection of the object to be detected specifically includes the following two ways, specifically referring to fig. 3 and 4 of the first embodiment of the semiconductor device for capacitance detection of the present invention, wherein the second embodiment, the third embodiment and other embodiments of the semiconductor device for capacitance detection of the present invention, which are not specifically described in the present specification and are within the protection scope of the present invention, can implement the capacitance detection of the object to be detected 2 in the following two ways:

the first mode is as follows: at the gate power supply V_GA constant first voltage is applied between the source S and the drain D of the semiconductor device; detecting the current flowing between the drain D and the source S to obtain the capacitance of the object 2 to be measured; the method being gate-source voltage V_GS(i.e., the voltage V between the first terminal of the capacitance detecting section and the source electrode_GS) And drain-source voltage V_DSBy detecting the drain-source current I_DSTo obtain the capacitance of the object 2.

The second mode is as follows: at the gate power supply V_GA constant first voltage is applied between the source S and the drain D of the semiconductor device, a constant first current is applied between the source S and the drain D of the semiconductor device, and the voltage between the source S and the drain D of the semiconductor device is detected to obtain the capacitance of the object 2 to be measured; the method being gate-source voltage V_GS(i.e., the voltage V between the first terminal of the capacitance detecting section and the source electrode_GS) And drain-source current I_DSBy detecting the drain-source voltage V_DS(i.e. the voltage V between the drain and the source_DS) To obtain the capacitance of the object 2.

In order to make it clear for those skilled in the art that the first mode is described as an example in the present specific embodiment, those skilled in the art can understand the second mode according to the principle described in the first mode, so as to better apply the semiconductor device for capacitance detection proposed in the present invention.

Referring again to fig. 3, in applying the semiconductor device for capacitance detection of the present invention, a circuit is constructed according to the structure shown in fig. 3 or 4, in which the gate power source V is provided_GConstant voltage is applied to the source S and the drain D to ensure the gate-source voltage V_GS(i.e., the voltage V between the first terminal of the capacitance detecting section and the source S_GS) Drain source voltage V_DSWithout change, in this first embodiment by detecting the drain-source current I_DSThe change in capacitance of the object 2 is determined, and thus the change in dielectric constant of the object 2 is obtained.

Source-drain current I due to the linear region of such a semiconductor device for capacitance detection as described above_DSComprises the following steps:

$I_{DS}\≅\frac{W}{L}{\mathrm{\μ}}_n{C}_{OX}(V_G-V_{th})V_D---\left(1\right)$

wherein W is the width of the ion sensitive membrane, L is the length of the ion sensitive membrane, mu_nFor effective electron mobility, C_OXCapacitance of ion sensitive membrane, V_DIs the drain voltage, V_GIs the gate voltage (i.e. gate supply), V_thIs the threshold voltage.

In the prior art, since a double charge layer is generated at a contact interface between an object to be measured and an ion sensitive membrane, only one layer of ion sensitive membrane is included in the process of detecting ion activity, and a reference electrode is introduced, as shown in fig. 9, a potential change diagram of the contact interface between the object to be measured and the ion sensitive membrane is shown. Wherein psi is determined by introducing a reference electrode in order to detect the ion activity of the analyte_MEIs constant, and the drain-source current I can be known according to the formula (1)_DSAnd a threshold voltage V_thDrain voltage V_DGrid power source V_GIt is related. While the measuring process maintains the first voltage V_GAnd a second voltage V_DA constant, third current, i.e. drain-source current I_DSOnly with the threshold voltage V_thIn this regard, the change in threshold voltage depends on the potential difference between the solution and the sensitive membrane interface, which is directly caused by the change in ionic activity of the solution.

In the embodiment of the present invention, the objective is to detect the change of the capacitance of the analyte 2, so that the change of the ion activity of the analyte 2 needs to be controlled first without affecting the change of the capacitance of the analyte 2, and in the present invention, the drain voltage V is ensured first_DGrid power source V_GAnd the ion sensitive membrane is unchanged, so the drain-source current I_DSIs varied by a threshold voltage V_thCaused by a change in (b); however, the change of the threshold voltage is related to both the capacitance of the analyte 2 and the ion activity of the analyte 2; therefore, it is a technical difficulty to ensure that the ion activity of the object 2 is not changed or that the change of the ion activity of the object 2 does not affect the detection of the capacitance of the object 2, and in order to solve the above technical problems, in the present invention, by introducing the first ion-sensitive film 31 and the second ion-sensitive film 32 (specifically, refer to the first to third embodiments) identical to the first ion-sensitive film 31, the potential changes caused by the double charge layers generated at the interfaces where the two ion-sensitive films are connected to the object 2 are mutually offset, and in the present invention, the ion-sensitive films and the gate power supply V are maintained_GIs constant, so the drain-source current I_DSIs only V with the threshold voltage_thOff, and the threshold voltage V_thIs related to the capacitance of the test object 2, so that the leakage current I can be detected_DSThe capacitance and the dielectric constant of the object 2 to be measured are obtained.

In order to solve the technical problem (1) in the background art, that is, the prior art potentiometric biosensor only detects the ion activity of the analyte, and the reflected information is too little to accurately describe the property of the analyte, which is inconvenient for further research, the present invention provides a dual-mode semiconductor device, which can detect the ion activity of the analyte 2 and the dielectric constant (capacitance) of the analyte 2, and specifically refer to fig. 11 to 13, where fig. 11 is a schematic structural diagram of a first embodiment of the dual-mode semiconductor device of the present invention, fig. 12 is a schematic structural diagram of a second embodiment of the dual-mode semiconductor device of the present invention, and fig. 13 is a schematic structural diagram of a third embodiment of the dual-mode semiconductor device of the present invention.

Before describing the structure of the dual-mode semiconductor device of the present invention in detail, please refer to fig. 10, which is a schematic structural diagram of the reference electrode 1 of the present invention. Wherein, for the reference electrode 1 of the invention, it is a Ag/AgCl reference electrode in general, it includes Ag core 1-1, wrap up a layer of AgCl layer 1-2 outside the core 1-1 of Ag, put into KCl saturated solution 1-3 together, seal in porous membrane or ion semi-permeable membrane and put it into 2 of determinants, in the course of detecting, will exert a voltage on said reference electrode 1, namely energize reference electrode 1, will produce a series of chemical reactions in AgCl layer 1-2 and said KCl saturated solution 1-3 contact interface, and will produce a voltage difference in said AgCl layer 1-2 and said KCl saturated solution 1-3 contact interfaceThe voltage difference is:

whereinIs chloride ion Cl^-So that the voltage difference can be derivedWith chloride ions Cl only^-And in general, a saturated KCl solution, the chloride ion Cl of which is normally used in the reference electrode 1^-Is constant, it is therefore possible to ensure a constant voltage in the solution, that is to say it is possible to ensure a constant voltage between the reference electrode 1 and the source electrode S of the dual-mode semiconductor device.

Referring first to fig. 11 to 13, fig. 11 is a structural view of a dual-mode semiconductor device according to a first embodiment of the present inventionFig. 12 is a schematic structural view of a dual-mode semiconductor device according to a second embodiment of the present invention, and fig. 13 is a schematic structural view of a dual-mode semiconductor device according to a third embodiment of the present invention. The dual-mode semiconductor device comprises a substrate B, a source S and a drain D which are arranged on the substrate B, wherein the semiconductor device also comprises a capacitance detection part, the capacitance detection part at least comprises a first ion sensitive film 31 and a second ion sensitive film 32 which is the same as the first ion sensitive film 31, an object to be detected 2 is arranged between the first ion sensitive film 31 and the second ion sensitive film 32, the first ion sensitive film 31 is connected with the substrate B, and the second ion sensitive film 32 and a grid power supply V are arranged between the second ion sensitive film 32 and the first ion sensitive film 31_GThe capacitance detection part is used for changing the capacitance at two ends of the capacitance detection part 2 based on the filling of the object 2 to be detected in the capacitance detection part, thereby the threshold voltage V of the semiconductor device_thAnd (6) changing. The capacitance of the object 2 to be measured can be obtained without using the reference electrode 1 in the dual-mode semiconductor device, the dielectric constant of the capacitance detection part is changed due to the filling of the object 2 to be measured in the capacitance detection part, so that the capacitance of the capacitance detection part is changed, and the grid power supply V_GThe capacitance voltage division is changed under the condition of no change, and the threshold voltage V of the semiconductor device connected with the capacitance voltage division is changed_th(ii) a change;

in addition, a reference electrode 1 is inserted into the object 2 to be measured for determining the threshold voltage V of the dual-mode semiconductor device_thObtaining the ion activity of the object 2 to be detected;

wherein, the first ion sensitive membrane 31 and the second ion sensitive membrane 32 are identical, no matter the material or the geometric dimension thereof; this is provided to avoid the influence of ion activity in the analyte 2 (for reasons described below), so that the capacitance of the analyte 2 can be accurately obtained.

The materials of the substrate B and the ion sensitive film are the same as those of the substrate B and the ion sensitive film in the semiconductor device for capacitance detection, and are not described herein again.

C: first embodiment of the dual-mode semiconductor device of the present invention

Referring to fig. 11, fig. 11 is a schematic structural diagram of a dual-mode semiconductor device according to a first embodiment of the present invention. In a preferred embodiment, the dual-mode semiconductor device includes a substrate B, a source S and a drain D disposed on the substrate, and a capacitance detection portion, the capacitance detection portion at least includes a first ion-sensitive film 31 and a second ion-sensitive film 32 identical to the first ion-sensitive film 31, an object 2 to be measured is disposed between the first ion-sensitive film 31 and the second ion-sensitive film 32, the first ion-sensitive film 31 is connected to the substrate B, and the second ion-sensitive film 32 is connected to a gate power supply V_GAre connected.

The second ion-sensitive film 32, the metal layer 11 and the electrolyte connected thereto in the capacitance detection portion are equivalent to a third capacitor 9, and the first ion-sensitive film 31 is a dielectric layer of the third capacitor 9 (see the equivalent circuit diagram of fig. 4), wherein the second ion-sensitive film 32 and the interface of the first ion-sensitive film 31 in contact with the object 2 form an electric double layer, where the two electric double layers are equivalent to a fifth capacitor 12 (an electric double layer formed by the interface of the first ion-sensitive film 31 in contact with the object 2) and a sixth capacitor 13 (an electric double layer formed by the interface of the second ion-sensitive film 32 in contact with the object 2) in fig. 4, respectively. In this embodiment, the first ion-sensitive film 31, the substrate B, the source S, the drain D and the solution portion can be regarded as a complete transistor, except that the gate insulating layer of the transistor is the first ion-sensitive film 31.

The reference electrode 1 is inserted into the object 2 to be detected and used for electrifying the reference electrode 1V after the capacitance detection of the object 2 to be detected is finished_G2For detecting the ionic activity of the analyte 2, the reference electrode 1According to the threshold voltage V of the dual-mode semiconductor device_thThe change of (2) obtains the ion activity of the analyte 2.

C1: second embodiment of the Dual-mode semiconductor device of the present invention

Referring to fig. 12, fig. 12 is a schematic structural diagram of a dual-mode semiconductor device according to a second embodiment of the present invention. Based on the structure of the first embodiment of the dual-mode semiconductor device according to the present invention, the gate insulating layer 5 is disposed on the substrate B, the gate insulating layer 5 is disposed between the substrate B and the first ion-sensitive film 31, and the gate electrode 4 is disposed between the gate insulating layer 5 and the first ion-sensitive film 31, in this embodiment, the first ion-sensitive film 31, together with the electrolyte and the semiconductor portion, is equivalent to the first capacitor 6 in fig. 6, and the metal layer and the electrolyte portion of the second ion-sensitive film 32, which are connected to each other, are equivalent to the second capacitor 7, wherein the second ion-sensitive film 32 and the interface where the first ion-sensitive film 31 and the object 2 are in contact form an electric double layer, and the two electric double layers are equivalent to the fifth capacitor 12 (the electric double layer formed by the interface where the first ion-sensitive film 31 and the object 2 are in contact) and the sixth capacitor 13 in fig. 6, respectively (the second ion-sensitive film 32 forms an electric double layer with the interface contacting the object 2), the first ion-sensitive film 31 is the dielectric layer of the first capacitor 6, the second ion-sensitive film 32 is the dielectric layer of the second capacitor 7, and the reference electrode 1 is inserted into the object 2 and used for electrifying the reference electrode 1 after the capacitance detection of the object 2 is finished, wherein V is formed by the electric double layer formed by the interface contacting the second ion-sensitive film 32 with the object 2 to be detected_G2For detecting the ion activity of the analyte 2, the reference electrode 1 is used for detecting the threshold voltage V of the dual-mode semiconductor device_thThe change of (2) obtains the ion activity of the analyte 2.

The semiconductor device for capacitance detection in the second embodiment can be regarded as one in which a gate electrode 4 and a gate insulating layer 5 are added, i.e., the first ion-sensitive film 31 is extended outward, in the semiconductor device for capacitance detection in the first embodiment.

In addition, referring to fig. 7, in the dual mode semiconductor device of the present invention, the gate electrode 4 is a metal layer; or the gate electrode 4 is a plurality of interconnected metal layers disposed in an insulating layer, and the plurality of interconnected metal layers are disposed between the gate insulating layer and the first ion sensitive film 31, in practical applications, generally, the gate electrode 4 is a plurality of interconnected metal layers disposed in an insulating layer, so as to improve stability of the device.

C2: third embodiment of the Dual-mode semiconductor device of the present invention

Referring to fig. 13, a schematic structural diagram of a third embodiment of a dual-mode semiconductor device according to the present invention is shown, in which a gate insulating layer 5 is further disposed on the substrate B, a gate electrode 4 is disposed on the gate insulating layer, the capacitance detection portion further includes a comb capacitor 8, the comb capacitor 8 includes a first group of comb electrodes and a second group of comb electrodes, the first group of comb electrodes is connected to the gate insulating layer 5, and the second group of comb electrodes is connected to the gate power source V_G1Be connected, first group of broach electrode parcel have first ion sensitive membrane 31, second group of broach electrode parcel have second ion sensitive membrane 32, just broach electric capacity 8 submergence in determinand 2 in, reference electrode 1 insert and locate determinand 2 in, be used for the electric capacity of determinand 2 detect the back that finishes, give reference electrode 1 circular telegram V_G2For detecting the ion activity of the analyte 2, the reference electrode 1 is used for detecting the threshold voltage V of the dual-mode semiconductor device_thThe change of (2) obtains the ion activity of the analyte 2.

In a preferred embodiment, the comb capacitor 8 comprises a fixed comb and a movable comb, the fixed comb electrode and the movable comb electrode are overlapped to form a decoupling comb capacitor, whereinThe movable comb teeth and the grid power supply V_G1The fixed comb teeth are connected with the grid insulation layer 5, or the fixed comb teeth are connected with the grid power supply V_G1The movable comb teeth are connected with the grid insulation layer 5; in addition, in another preferred embodiment, the comb teeth of the comb-tooth capacitor 8 are all fixed comb teeth, and are not described herein again.

The three embodiments described above are only three preferred embodiments of the dual-mode semiconductor device in the present invention, and it should not be understood that the present invention only includes the three embodiments described above, and therefore, any technical solution that relates to detection of ion activity and capacitance of the analyte 2 at the same time is within the scope of the present invention.

As can be seen from the structure of the dual-mode semiconductor device, the dual-mode semiconductor device provided in the present invention can conveniently detect the capacitance and the ion activity of the object 2, for convenience of description, a first operation mode and a second operation mode are introduced in the present specification, and the structure of the first embodiment of the dual-mode semiconductor device in the present invention is taken as an example for description, where the first operation mode is to detect the capacitance of the object 2, that is, a case where the energized reference electrode 1 is not inserted into the object 2 or the energized reference electrode 1 inserted into the object 2 is not energized; the second operation mode is to detect the ion activity of the object 2, that is, in the case of the first operation mode, the energized reference electrode 1 is inserted into the object 2, or the energized reference electrode inserted into the object is energized, or the gate power supply stops working, and the energized reference electrode 1 inserted into the object 2 is energized; the basic structure and principle of the first operating mode are the same as those of the semiconductor device for capacitance detection described above, and modifications thereof are also described above, and thus are not described herein again; for the second operation mode, please refer to fig. 11 specifically.

When the dual-mode semiconductor device of the present invention is used, the method is:

(a) in the first working mode, when a reference electrode is not inserted into the object to be measured or when the reference electrode inserted into the object to be measured is not electrified, detecting the capacitance of the object to be measured;

(b) and inserting the reference electrode into the object to be detected and electrifying the reference electrode, namely detecting the ion activity of the object to be detected in the second working mode.

The specific operation in step (a) is similar to the operation and principle of the semiconductor device for capacitance detection, and is not described herein again. After the capacitance of the object 2 to be measured is detected, the reference electrode 1 is inserted into the object 2 to be measured, and at this time, because the reference electrode 1 is directly contacted with the object 2 to be measured, the first grid voltage V added in the capacitance detection is_G1Is applied to the object 2 by capacitive coupling, so that the first gate voltage V is applied after the reference electrode 1 is inserted into the object 2_G1The voltage applied to the test object is negligible, and the voltage in the test object is provided by the reference electrode, and the first grid voltage V can be controlled_G1Is 0, so that only the voltage on the reference electrode 1 needs to be taken into account.

Then, an electric double layer V is formed at a portion where the analyte 2 is in contact with the first ion-sensitive film 31_EDLThe double charge layer V_EDLIs related to the ion activity of the object 2 to be measured, resulting in a threshold voltage V of the dual-mode semiconductor device_thAs well as changes.

Thirdly, when the grid voltage is larger than the threshold voltage V_thI.e. the current I between the drain and the source when the device is in the on-state_DSComprises the following steps:

$I_{DS}\≅\frac{W}{L}{\mathrm{\μ}}_n{C}_{OX}(V_G-V_{th})V_D$ (Linear region Source-Drain Current) (3.1)

$I_{DS}\≅\frac{W}{2L}{\mathrm{\μ}}_n{C}_{OX}{(V_G-V_{th})}^2$ (saturated region Source-Drain Current) (3.2)

Wherein W is the width of the first ion-sensitive membrane 31, L is the length of the first ion-sensitive membrane 31, μ_nFor effective electron mobility, C_OXIs the capacitance, V, of the first ion-sensitive membrane 31_DIs the drain voltage, V_GIs the gate voltage, V_thIs the threshold voltage.

Therefore, it can be derived from the above equation (3.1) and equation (3.2), wherein the current I is obtained when the voltage between the reference electrode 1 and the source electrode S is kept constant and the voltage between the drain electrode D and the source electrode S is ensured to be constant_DSWill follow the threshold voltage V_thMay be changed. Therefore, the current I can be detected_DSTo obtain a threshold voltage V_thOf the threshold voltage V_thIs determined by the ion activity of the ions in the analyte 2, and due to the above-mentioned setting, the change in ion activity only uniquely causes the threshold voltage V_thCan be detected by detecting the current I_DSTo obtain a change in ion activity.

The semiconductor device for capacitance detection solves the problems that the detection of the electrolyte capacitance generally needs a complex driving circuit and a signal processing circuit, the cost is high and the application range is limited at present, and has simple structure and wide application range.

By adopting the dual-mode semiconductor device, the problem that the ion activity of the object to be detected is detected only through charge change in the prior art is solved, the accuracy of describing the property of the object to be detected is improved, the follow-up research is facilitated, and the dual-mode semiconductor device is simple in structure, high in accuracy and wide in application range.

In this specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Claims (12)

1. The semiconductor device comprises a substrate, a source electrode and a drain electrode, wherein the source electrode and the drain electrode are arranged on the substrate, the semiconductor device is characterized by further comprising a capacitance detection part, the capacitance detection part at least comprises a first ion sensitive film and a second ion sensitive film which is the same as the first ion sensitive film, an object to be detected is arranged between the first ion sensitive film and the second ion sensitive film, the first ion sensitive film is connected with the substrate, the second ion sensitive film is connected with a gate electrode, and the capacitance detection part is used for changing the capacitance at two ends of the capacitance detection part based on the filling of the object to be detected in the capacitance detection part, so that the threshold voltage of the semiconductor device is changed.

2. The semiconductor device for capacitance detection according to claim 1, wherein a gate insulating layer is provided between the substrate and the first ion-sensitive film, and a gate electrode is provided between the gate insulating layer and the first ion-sensitive film.

3. The semiconductor device for capacitance detection according to claim 2, wherein the gate electrode is a metal layer; or the gate electrode is a plurality of interconnected metal layers arranged in an insulating layer, and the plurality of interconnected metal layers are arranged between the gate insulating layer and the first ion sensitive film.

4. The semiconductor device for capacitance detection according to claim 1, wherein a gate insulating layer is further disposed on the substrate, a gate electrode is disposed on the gate insulating layer, the capacitance detection portion further comprises a comb capacitor, the comb capacitor comprises a first set of comb electrodes and a second set of comb electrodes, the first set of comb electrodes are all connected to the gate electrode, the second set of comb electrodes are all connected to a gate power source, the first set of comb electrodes are wrapped with a first ion sensitive film, the second set of comb electrodes are wrapped with a second ion sensitive film, and the comb capacitor is immersed in the object to be detected.

5. A method for realizing capacitance detection of an object to be detected based on the semiconductor device as claimed in any one of claims 1 to 4, the method comprising:

applying a constant first voltage between the gate power supply and the source, and a constant second voltage between the source and the drain of the semiconductor device; detecting the current flowing between the drain electrode and the source electrode to obtain the capacitance of the object to be detected;

or the method comprises the following steps:

and applying a constant third voltage between the gate power supply and the source electrode, applying a constant first current between the source electrode and the drain electrode of the semiconductor device, and detecting the voltage between the source electrode and the drain electrode of the semiconductor device to acquire the capacitance of the object to be detected.

6. A dual-mode semiconductor device comprises a substrate, a source electrode and a drain electrode, wherein the source electrode and the drain electrode are arranged on the substrate, and the dual-mode semiconductor device is characterized in that:

the dual-mode semiconductor device further comprises a capacitance detection part, wherein the capacitance detection part at least comprises a first ion sensitive film and a second ion sensitive film which is the same as the first ion sensitive film, an object to be detected is arranged between the first ion sensitive film and the second ion sensitive film, the first ion sensitive film is connected with the substrate, the second ion sensitive film is connected with a gate power supply, and the capacitance detection part is used for changing the capacitance at two ends of the capacitance detection part based on the filling of the object to be detected in the capacitance detection part, so that the threshold voltage of the dual-mode semiconductor device is changed;

and the reference electrode is inserted into the object to be tested and used for obtaining the ion activity of the object to be tested according to the change of the threshold voltage of the dual-mode semiconductor device.

7. The semiconductor device for capacitance detection according to claim 6, wherein a gate insulating layer is provided between the substrate and the first ion-sensitive film, and a gate electrode is provided between the gate insulating layer and the first ion-sensitive film.

8. The semiconductor device for capacitance detection according to claim 7, wherein the gate electrode is a metal layer; or the gate electrode is a plurality of interconnected metal layers arranged in an insulating layer, and the plurality of interconnected metal layers are arranged between the gate insulating layer and the first ion sensitive film.

9. The semiconductor device for capacitance detection according to claim 6, wherein a gate insulating layer is further disposed on the substrate, a gate electrode is disposed on the gate insulating layer, the capacitance detection portion further comprises a comb capacitor, the comb capacitor comprises a first set of comb electrodes and a second set of comb electrodes, the first set of comb electrodes are all connected to the gate electrode, the second set of comb electrodes are all connected to a gate power source, the first set of comb electrodes are wrapped with a first ion sensitive film, the second set of comb electrodes are wrapped with a second ion sensitive film, and the comb capacitor is immersed in the object to be detected.

10. A method for simultaneously detecting capacitance and ion activity of an analyte based on the dual-mode semiconductor device as claimed in any one of claims 6 to 9, the method comprising the steps of:

(a) detecting the capacitance of the object to be detected when the reference electrode is not inserted into the object to be detected or when the reference electrode inserted into the object to be detected is not electrified;

(b) and inserting the reference electrode into the object to be detected and electrifying the reference electrode to detect the ion activity of the object to be detected.

11. The method for simultaneously detecting the capacitance and the ionic activity of the analyte according to claim 10, wherein the step (a) is specifically as follows:

applying a constant first voltage between a gate power supply and a source of said dual mode semiconductor device and a constant second voltage between a source and a drain of said dual mode semiconductor device; detecting the current flowing between the drain electrode and the source electrode to obtain the capacitance of the object to be detected;

or applying a constant third voltage between the gate power supply and the source of the dual-mode semiconductor device, applying a constant first current between the source and the drain of the dual-mode semiconductor device, and detecting the voltage between the source and the drain of the dual-mode semiconductor device to obtain the capacitance of the object to be measured.

12. The method for simultaneously detecting the capacitance and the ionic activity of the analyte according to claim 10, wherein the step (b) is specifically as follows:

applying a constant fourth voltage to the reference electrode, applying a constant fifth voltage between the source and the drain, and detecting the current flowing between the drain and the source to obtain the ion activity of the analyte;

or applying a constant second current between the source and the drain of the dual-mode semiconductor device, applying a constant sixth voltage between the source and the reference electrode of the dual-mode semiconductor device, and detecting the voltage between the drain and the source of the dual-mode semiconductor device to obtain the ion activity of the analyte.