CN104280443B

CN104280443B - A kind of making of highly sensitive OTFT pH sensors and pH detections

Info

Publication number: CN104280443B
Application number: CN201310282472.6A
Authority: CN
Inventors: 曾红娟; 谢光忠; 蒋亚东
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2013-07-08
Filing date: 2013-07-08
Publication date: 2017-12-19
Anticipated expiration: 2033-07-08
Also published as: CN104280443A

Abstract

The pH made it is an object of the invention to provide a kind of preparation method of highly sensitive OTFT pH sensors and of this OTFT devices is verified.It is using the manufacture craft of conventional semiconductor devices first, prepares the slotted TFT devices of gate strip, and this device is packaged by existing packaging technology.By using electrochemical deposition electronic polymer film in the region that grid is slotted, OTFT pH sensors are made.The device of preparation is tested its pH sensitivity characteristic in the solution using characteristic of semiconductor tester, it was found that in the range of the pH of solution is 2 to 7, there is good linear relationship between the threshold voltage and pH of OTFT devices, the slope of its straight line is 0.955V/pH.Than common ISFET devices to H⁺Sensitivity be higher by 15 times.

Description

A kind of making of highly sensitive OTFT pH sensors and pH detections

Technical field

The present invention relates to a kind of making of highly sensitive organic field-effect tube transistor (OTFT) pH sensors, it is special It is related to the technology of preparing of semiconductor devices and electronic polymer film.

Background technology

21st century is the century of a biology and information, around biology and the research of life science, how have been gathered Information and then use such information for instructs the production practices activity of people to be only people constantly to explore and the purpose of research. PH value is more and more increasingly related to our production and life, this correlation not only show industry, agricultural, national defence and Science and technology etc., it is also manifested by the various aspects such as diet, digestion, metabolism etc. of our lives.Thus to pH's Measurement and control have become more and more important problem.

Buffer system present in blood of human body as shown in Figure 1, its pH value controls carries out phase in a narrow range The biochemical reaction answered.Therefore, detection in real time is carried out accurately to the pH value of a narrow range, there is very important meaning.

The content of the invention

It is an object of the invention to provide a kind of preparation method of highly sensitive OTFT pH sensors.

The present invention includes herein below：

First, a transistor with Trenched gate is prepared using semiconductor silicon technique.

2nd, electronic polymer film is deposited in the slotted zones of grid using the method for electrochemical deposition.

3rd, pH detections are carried out to the cushioning liquid of different pH value with the transistor device that deposited electronic polymer film.

First, the preparation method of the transistor provided by the invention with Trenched gate is as follows：

(1) certain thickness field oxide is grown；

(2) photolithographic source, drain region：Positive photoresist；

(3) glue phosphorus injection (forming source S, leakage D areas) is stayed；

(4) photolithographic substrates contact hole：Positive photoresist；

(5) glue boron is stayed to inject；

(6) remove photoresist；

(7) photoetching active area (grid G areas, source aperture area, small opening area)：Positive photoresist；

(8) SiO is corroded₂Layer；

(9) certain thickness gate oxide is grown；

(10) photolithography contact lead porose area：Positive photoresist；

(11) certain thickness metallic aluminium is sputtered；

(12) metal area is anti-carved using negative photoresist, removes part of metal grid, the obtained crystalline substance with Trenched gate Body pipe is as shown in Figure 2；

(13) device of preparation is packaged by traditional semiconductor technology.

2nd, the method provided by the invention using electrochemical deposition deposits the system of electronic polymer film in the slotted zones of grid Preparation Method is as follows：

(I) using the grid of packaged field-effect transistor as working electrode, a platinum electrode is that one full to electrode It is reference electrode with calomel electrode, puts into the electrolyte prepared in advance, its experimental provision is as shown in Figure 3.

(II) unipotential step chronoamperometry is selected, constant-potential electrolysis is carried out to working electrode to be plated, electrification is set The instrument parameter of work station is learned, deposits electronic polymer film.

(III) preparation of electrolyte：The electronic polymer monomer of respective volume is pipetted by a certain percentage, and acid, and salt are used in combination Deionized water dilutes the mixed liquor for being configured to certain volume.

(IV) structure that the transistor of electronic polymer film is deposited in the slotted zones of grid prepared by is as shown in Figure 4.

3rd, the transistor device provided by the invention that deposited electronic polymer film enters to the cushioning liquid of different pH value The method of row pH detection checkings is as follows：

(A) a test mould is set on characteristic of semiconductor tester to the OTFT devices of the n- raceway grooves of this depletion type Type, source device, the drain electrode SMU with instrument respectively₁And SMU₂Be connected, the grid of device, substrate respectively with the SMU3 of instrument and GNDU () be connected.

(B) the OTFT devices of preparation are immersed in different pH cushioning liquid, then according to test block diagram pair shown in Fig. 5 The performance of OTFT devices is tested.

Brief description of the drawings：

PH buffer systems present in Fig. 1 blood

Fig. 2 has the transistor arrangement profile of Trenched gate, wherein 1：Source electrode, 2：Grid, 3：Groove, 4：Drain electrode

Fig. 3 deposits the Experimental equipment of electronic polymer film in the slotted zones of grid,

Wherein 5：To electrode, 6：Reference electrode, 7：Working electrode

Fig. 4 deposits the transistor junction composition of electronic polymer film in the slotted zones of grid, W groove widths in figure,

L channel lengths, G grids, S source electrodes, D drain electrodes, B substrates, 6：Reference electrode,

8：Solution to be measured；9：PEDOT films, 10：Epoxy packages

Fig. 5 OTFT device detections pH test block diagram, wherein：6：For reference electrode, 11：Cushioning liquid

Fig. 6 OTFT devices are to H ion-sensitive characteristics

Embodiment

Making depletion type OTFT pH sensors provided by the invention and pH detections concrete mode are as follows：

1) field oxide is grown：Thickness d=402nm.

2) photolithographic source, drain region：Positive photoresist.

3) glue phosphorus injection (forming source, drain region) is stayed：80Kev, implantation dosage 4.0 × 10¹⁵Individual phosphorus atoms/m³So that partly lead The resistivity of body is 0.7-1 Ω .cm.

4) photolithographic substrates contact hole：Positive photoresist.

5) glue boron is stayed to inject：60Kev, implantation dosage 4.0 × 10¹⁵Individual phosphorus atoms/m³。

6) remove photoresist.

7) photoetching active area (grid region, source aperture area, small opening area)：Positive photoresist.

8) SiO is corroded₂Layer (100nm).

9) gate oxide is grown：Thickness d=85nm, 1000 DEG C of temperature so that surface charge density≤4.0 × 10¹¹/cm²。

10) photolithography contact lead porose area：Positive photoresist.

11) splash-proofing sputtering metal aluminium：Thickness d=60nm/120nm.

12) metal area is anti-carved using negative photoresist, removes the metal gate that partial width is 35 microns.

13) device of preparation is packaged by traditional semiconductor technology.

14) using packaged OTFT grid as working electrode, a platinum filament is to electrode, and saturated calomel electrode is ginseng Than electrode, put into the electrolyte prepared in advance and include：Electronic polymer monomer 3,4-ethylene dioxythiophene (EDOT) concentration is 1.8×10^-2Mol/L, 0.1 gram of potassium nitrate/person of outstanding talent rise, the phosphate buffer solution of pH4.0 0.1 mol/L, using unipotential Step chronoamperometry, constant potential 0.8V, electrolysis time 10 minutes, poly- 3,4- enedioxies thiophene is obtained on OTFT grid Fen (PEDOT) film, about 2.6 microns of thickness.

15) test model is set on keilethy-4200 tester, source device, drain electrode respectively with The SMU of instrument₁And SMU₂Be connected, the grid of device, substrate respectively with the SMU3 and GNDU of instrument () be connected, then OTFT Device is immersed in different pH cushioning liquid, and the voltage between fixed source and drain is 2V, changes the voltage between grid source, measuring appliance Curent change between the drain-source of part, the OTFT devices measured are to H ion-sensitives characteristic as shown in fig. 6, can from Fig. 6 Go out, in the range of the pH of solution is 2 to 7, have good linear relationship between the pinch-off voltage and pH of OTFT devices, its is straight The slope of line is 0.955V/pH.It is than common ISFET devices to H⁺Sensitivity be higher by 15 times.

Claims

1. a kind of preparation method of highly sensitive OTFT pH sensors, it is characterised in that comprise the following steps：

(1) certain thickness field oxide is grown；

(2) using positive photoresist photolithographic source, drain region；

(3) glue phosphorus is stayed to inject the source of being formed, drain region；

(4) positive photoresist photolithographic substrates contact hole is used；

(5) glue boron is stayed to inject；

(6) remove photoresist；

(7) positive photoresist photoetching active area is used, the active area includes grid region, source aperture area, small opening area；

(8) SiO2 layers are corroded：

(9) certain thickness gate oxide is grown；

(10) positive photoresist photolithography contact lead porose area is used；

(11) certain thickness metallic aluminium is sputtered；

(12) metal area is anti-carved using negative photoresist, removes part of metal grid, the transistor with Trenched gate is made；

(13) device of preparation is packaged by traditional semiconductor technology；

(14) it is to electricity using the grid of the packaged transistor (TFT) with Trenched gate as working electrode, a platinum filament Pole, saturated calomel electrode are reference electrode, are put into the electrolyte prepared in advance using electrochemical method with Trenched gate The gate deposition electronic polymer film of transistor (TFT) organic field-effect tube transistor (OTFT) pH sensors are made, it is described Electrolyte includes electronic polymer monomer, salt and phosphate buffer solution.

2. the preparation method of highly sensitive OTFT pH sensors according to claim 1, it is characterised in that：Used Electronic polymer monomer include thiophene-based, phenyl amines, pyrroles's type organic.

A kind of 3. verification method of pH sensors according to claim any one of 1-2, it is characterised in that：To depletion type When the OTFT devices of n- raceway grooves are measured with characteristic of semiconductor tester, need first to set a test mould on tester Type, source device, drain electrode are connected with the SMU1 and SMU2 of instrument respectively, the grid of device, the substrate SMU3 with instrument respectively With GNDU () be connected.

4. the verification method of highly sensitive OTFT pH sensors according to claim 3, it is characterised in that：Preparation OTFT devices be first immersed in different pH cushioning liquid, then pH value of solution is detected, establishes threshold value during different pH Electric potential relation figure, so that it may assess its sensitivity.