CN101661943A - Monolithic integrated ultraviolet image sensor, pixel units and preparation method thereof - Google Patents
Monolithic integrated ultraviolet image sensor, pixel units and preparation method thereof Download PDFInfo
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- CN101661943A CN101661943A CN200810118875A CN200810118875A CN101661943A CN 101661943 A CN101661943 A CN 101661943A CN 200810118875 A CN200810118875 A CN 200810118875A CN 200810118875 A CN200810118875 A CN 200810118875A CN 101661943 A CN101661943 A CN 101661943A
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Abstract
The invention discloses an ultraviolet image sensor, and pixel units and a preparation method thereof. The ultraviolet image sensor comprises a row scanning/drive circuit, a column signal reading/drive circuit and a pixel array; each pixel unit comprises a signal amplifier circuit and an optical detection element; the row scanning/drive circuit and the column signal reading/drive circuit of the image sensor, and the signal amplifier circuit of each pixel unit are all manufactured by adopting silicon CMOS technology, and are synchronously integrated on the same substrate; the optical detectionelement is positioned above the signal amplifier circuit; and the optical detection element and the signal amplifier circuit are isolated by a medium layer and are electrically connected through a through hole of the medium layer. Monolithic integration is realized, so the ultraviolet image sensor has higher performance and lower cost, and the resolution and sensibility are considerably improved.
Description
Technical field
The invention relates to image sensor technologies, be specifically related to a kind of monolithic integrated ultraviolet image sensor and pixel cell thereof, and the ultraviolet image sensor preparation method.
Background technology
Ultraviolet (UV) Detection Techniques are a kind of novel photoelectric-detection technology that grow up after infrared and laser acquisition technology.Its application is very extensive, from the study of high energy physics to the space exploration, observe medical science and biological detections such as cancer cell, microbe, hemochrome, white blood cell, red blood cell, nucleus from the cutaneous lesions details, the calamity forecast under daytime weak light source condition is monitored organic contamination to air remote sensing; From the communication of satellite ultraviolet to military electrooptical countermeasures and infrared/ultraviolet dual wave-band guidance etc. all be unable to do without advanced ultraviolet detection technology.
Current people are growing to the demand of ultraviolet detection technology and device.Advanced ultraviolet detection adopts photomultiplier to be equipped with expensive optics colour filter more, and its sensitivity is subjected to the restriction of filter transmitance and photocathode quantum efficiency, and its volume and weight are big simultaneously, the operating voltage height, and the photocathode quantum efficiency is low.And photomultiplier is that electrical resistivity survey is surveyed, and needs scanning imagery.And the silica-based CCD of dorsal part attenuate (opto-electronic conversion formula imageing sensor) is very high to the sensitivity of visible light, and very low to the sensitivity of ultraviolet light, especially to vacuum ultraviolet (VUV), visible light is also very big to its influence.In addition, the CCD low-dark current is bigger.In order to suppress dark signal, CCD must work at low temperatures, has so just strengthened technical difficulty and cost.The radiation-resistant property of CCD is very poor in addition, and this not only can cause decrease in image quality, but also can influence the charge collection efficiency of passage, brings array manifold corresponding inhomogeneous.
Ultraviolet sensor has experienced from ultravioplet photomultiplier to ultraviolet alignment multielement bar, arrives the development course of ultraviolet image sensor spare again.Ultraviolet image sensor is not only the essential core devices of high-end application such as modern space technology, also can develop into the general low side product for civilian use on demand.Although the vacuum ultraviolet (VUV) image device is in leading position aspect ultraviolet astronomy at present, because inherent huge advantage, popularizing of the outer picture pick-up device of solid violet has been trend of the times.For this reason, the semi-conducting material and the application of searching and development of new, and new integrated technology is the important directions of solid ultraviolet image sensor development.Simultaneously, because UV signal is usually fainter, therefore, one of key that to have highly sensitive ultraviolet transducing device also be the ultraviolet detection technology of development of new.
Summary of the invention
The present invention has overcome deficiency of the prior art, provides a kind of single chip integrated sensitivity and resolution high ultraviolet image sensor structure and pixel unit thereof, and the preparation method of ultraviolet image sensor.
Technical scheme of the present invention is:
A kind of ultraviolet image sensor, comprise line scanning/drive circuit, column signal is read/drive circuit and pel array, it is characterized in that, described pixel cell comprises signal amplifier circuit and optical detection device, line scanning/the drive circuit of described imageing sensor, column signal reads/and the signal amplifier circuit of drive circuit and pixel cell all adopts silicon CMOS fabrication techniques, be integrated in same substrate synchronously, and optical detection device is positioned on the signal amplifier circuit, be provided with buffer layer between described optical detection device and the described signal amplifier circuit, both realize being electrically connected by the through hole of above-mentioned buffer layer.
Described optical detection device is photo resistance, Schottky diode, pn junction diode or thin-film transistor.
The semiconductor active layer of described optical detection device is metal oxide semiconductor films or other compound semiconductor film of energy gap greater than 3eV.
A kind of pixel cell structure of ultraviolet image sensor, it is characterized in that, comprise signal amplifier circuit and optical detection device, wherein, signal amplifier circuit is integrated on the substrate of ultraviolet image sensor, and optical detection device is positioned on the amplifier circuit, is provided with buffer layer between described optical detection device and the described amplifier circuit, and both realize being electrically connected by the through hole of above-mentioned buffer layer.
A kind of preparation method of ultraviolet image sensor, its step comprises:
1) on silicon substrate, adopt standard CMOS process to make line scanning/drive circuit, column signal to read/drive circuit, the signal amplifier circuit of pixel cell, preparation technology lasts till metallization and separator deposit;
2) adopt chemico-mechanical polishing (CMP) technology that buffer layer is carried out planarization;
3) adopt the interconnection technique of CMOS technology on the buffer layer of planarization, to form metal closures, as the signal amplification circuit of pixel cell and the electric connector of optical detection device;
4) on the dielectric layer after the planarization, carry out the making of optical detection device, make ultraviolet image sensor.
The optical detection device of described step 4) is thin-film transistor in this way, and its making step comprises:
1) deposit layer of metal film on the separator behind the process CMP, photoetching and etching form the gate electrode of thin-film transistor then;
2) deposit one deck dielectric insulating film is as the gate medium of thin-film transistor;
3) with deposit growth one deck wide bandgap semiconductor film, photoetching and etching form the active area of thin-film transistor then;
4) photoetching forms the contact hole that is connected with lower-layer wiring with etching gate insulation dielectric layer;
5) deposit layer of conductive film after the photoetching, and adopt lift-off technology to form the source-drain electrode of thin-film transistor, this source-drain electrode links to each other with the lower floor line by contact hole;
6) deposit one deck passivation layer of ultraviolet light thoroughly, and photoetching and etching provide lead terminal.
The figure processing of the gate electrode film of the step 1) of preparation thin-film transistor also can be taked the method peeled off.
The figure processing of the semiconductive thin film of the step 3) of preparation thin-film transistor also can be adopted the method for peeling off.
Compared with prior art, the invention has the beneficial effects as follows:
Ultraviolet image sensor of the present invention is compared with other solid violet outer sensor, has three big advantages: (1) pixel sensor cell itself is built-in, and signal is read/amplifier circuit, can realize that high sensitivity and high-resolution survey; (2) pixel sensor cell and scanning/read/drive circuit can be integrated in same chip, i.e. " monolithic is integrated " synchronously." monolithic is integrated " makes transducer have that performance is higher, cost is lower, volume/weight is littler, and reliability is advantages of higher more.In addition, monolithic is integrated to be complete silicon base CMOS technology based on maturation, so development space is huge; (3) optical detection device can adopt the thin-film transistor of three terminal device.Fa Ming optical detection device is two terminal device so far.Film transistor device has signal amplifying function under certain biasing, therefore have higher sensitivity.
Description of drawings
Fig. 1 a is the pixel cell structure schematic diagram of ultraviolet image sensor of the present invention;
Fig. 1 b is the floor map of ultraviolet image sensor of the present invention;
Fig. 2 is reading/drive circuit and amplifier circuit processing worker process schematic representation of ultraviolet image sensor;
Fig. 3 is separator deposit and chemico-mechanical polishing (CMP) and the ready-made process schematic representation of metal closures;
Fig. 4 is the process schematic representation that the detecting element of ultraviolet image sensor forms;
Fig. 5 is the process sequence diagram that the gate electrode of the optical detection device of pixel cell forms;
Fig. 6 is the process sequence diagram that the gate medium of the optical detection device of pixel cell forms;
Fig. 7 is the process sequence diagram that the active area of the optical detection device of pixel cell forms;
Fig. 8 is the process sequence diagram that the source-drain electrode contact hole of the optical detection device of pixel cell forms;
Fig. 9 is the process sequence diagram that the source-drain electrode of the optical detection device of pixel cell forms;
Figure 10 is the ready-made process sequence diagram of channel region passivation layer of the optical detection device of pixel cell.
Embodiment
Below in conjunction with the drawings and specific embodiments the present invention is described in further detail:
With reference to figure 1, ultraviolet image sensor of the present invention comprises line scanning/drive circuit, column signal to be read/drive circuit, pel array.Pixel cell contains signal amplifier circuit and optical detection device.Signal amplifier circuit has that signal reads, amplification and processing capacity.Described line scanning/drive circuit, column signal read/and the signal amplifier circuit of drive circuit, pixel cell all adopts silicon CMOS fabrication techniques, is integrated in same silicon substrate synchronously.The signal amplifier circuit of pixel cell and optical detection device be not or not same plane.Amplifier circuit is formed at silicon substrate, be in the bottom, and optical detection device is formed on the amplifier circuit.Isolate by dielectric layer between optical detection device and the amplifier circuit, realize being electrically connected by the through hole on the buffer layer.Optical detection device is a kind of in following device (unit) part: photo resistance, Schottky diode, pn junction diode and thin-film transistor.The light-sensitive material of optical detection device is metal oxide semiconductor films or other semiconductive thin film of energy gap greater than 3eV.
One specific embodiment of ultraviolet image sensor manufacture method of the present invention comprises Fig. 2 to Fig. 5:
(1) as shown in Figure 2, adopting the monocrystalline silicon disk is substrate 1.On silicon substrate, adopt standard CMOS process to make line scanning/drive circuit, column signal to read/amplifier circuit 3 of drive circuit 2 and pixel cell.Preparation technology lasts till metallization, promptly forms interconnection line 40,41,42 between device and circuit etc.Deposit 300～600 nano silicons are as buffer layer 5 then.
(2) adopt chemico-mechanical polishing (CMP) technology that buffer layer is carried out planarization.
(3) as shown in Figure 3, adopt the interconnection technique of CMOS technology on the buffer layer 5 of planarization, to form metal closures 6, as the electric connector of amplifier circuit 3 with optical detection device.
(4) as shown in Figure 4, on the dielectric layer after the planarization 5, carry out the making of optical detection device 7.
(1) as shown in Figure 5, the metal A l film of magnetron sputtering deposit one deck 50～200 nanometer thickness on the buffer layer 5 behind the process CMP, photoetching and etching form transistorized gate electrode 4 then.This gate electrode 4 links to each other with the corresponding metal wiring 40 of bottom amplifier circuit by the metal closures on the buffer layer 6.
(2) as shown in Figure 6, use the HfO of magnetically controlled sputter method deposit one deck 100～300 nanometer thickness
2Dielectric insulating film 8 is as transistorized gate medium.
(3) as shown in Figure 7, adopt the Mg of radio frequency magnetron sputtering method deposit one deck 20nm～150nm
xZn
(1-x)O (a kind of metal-oxide semiconductor (MOS) of broad stopband, x=0～0.35), photoetching and etching form transistorized active area 9 then.
(4) as shown in Figure 8, photoetching forms the contact hole 61,62 that the source transistor leakage is connected with lower- layer wiring 41,42 with etching gate insulation dielectric layer 8.
(5) as shown in Figure 9, the metal A l film of sputter one deck 50～200 nanometer thickness after the photoetching adopts lift-off technology to form transistorized source electrode 10 and drain electrode 11 then.
(6) as shown in figure 11, the high-purity silicon dioxide passivation layer 100 of deposit one deck 20～300 nanometer thickness (high pure silicon dioxide do not absorb ultraviolet ray), and photoetching and etching provide lead terminal, and enter backend process and encapsulation.
Wherein, the figure of gate electrode film processing can be taked the method peeled off, and simultaneously, the processing of the figure of ZnMgO film also can be adopted the method for peeling off.
More than by specific embodiment ultraviolet image sensor provided by the present invention, its pixel cell and preparation method have been described, it will be understood by those of skill in the art that in the scope that does not break away from essence of the present invention, can make certain deformation or modification to the present invention; Its preparation method also is not limited to disclosed content among the embodiment.
Claims (8)
1, a kind of ultraviolet image sensor, comprise line scanning/drive circuit, column signal is read/drive circuit and pel array, it is characterized in that, described pixel cell comprises signal amplifier circuit and optical detection device, line scanning/the drive circuit of described imageing sensor, column signal reads/and the signal amplifier circuit of drive circuit and pixel cell all adopts silicon CMOS fabrication techniques, be integrated in same substrate synchronously, and optical detection device is positioned on the signal amplifier circuit, be provided with buffer layer between described optical detection device and the described signal amplifier circuit, both realize being electrically connected by the through hole of above-mentioned buffer layer.
2, ultraviolet image sensor as claimed in claim 1 is characterized in that, described optical detection device is photo resistance, Schottky diode, pn junction diode or thin-film transistor.
3, ultraviolet image sensor as claimed in claim 1 or 2 is characterized in that, the semiconductor active layer of described optical detection device is metal-oxide semiconductor (MOS) or other semiconductive thin film of energy gap greater than 3eV.
4, a kind of pixel cell structure of ultraviolet image sensor, it is characterized in that, comprise signal amplifier circuit and optical detection device, wherein, signal amplifier circuit is integrated on the substrate of ultraviolet image sensor, and optical detection device is positioned on the signal amplifier circuit, is provided with buffer layer between described optical detection device and the described signal amplifier circuit, and both realize being electrically connected by the through hole of above-mentioned buffer layer.
5, a kind of preparation method of ultraviolet image sensor, its step comprises:
1) on silicon substrate, adopt standard CMOS process to make line scanning/drive circuit, column signal to read/drive circuit, the signal amplifier circuit of each pixel sensor cell, preparation technology lasts till metallization and buffer layer deposit;
2) adopt chemical Mechanical Polishing Technique that buffer layer is carried out planarization;
3) adopt the interconnection technique of CMOS technology on the buffer layer of planarization, to form metal closures, as the signal amplification circuit of pixel cell and the electric connector of optical detection device;
4) on the buffer layer after the planarization, carry out the making of the optical detection device of each pixel cell, make ultraviolet image sensor.
6, preparation method as claimed in claim 5 is characterized in that, the optical detection device of described step 4) is a thin-film transistor, and its making step comprises:
1) deposit layer of metal film on the separator behind the process CMP, photoetching and etching form the gate electrode of thin-film transistor then;
2) deposit one deck dielectric insulating film is as the gate medium of thin-film transistor;
3) with deposit growth one deck wide bandgap semiconductor film, photoetching and etching form the active area of thin-film transistor then;
4) photoetching forms the contact hole that is connected with lower-layer wiring with etching gate insulation dielectric layer;
5) deposit layer of conductive film after the photoetching, and adopt lift-off technology to form the source-drain electrode of thin-film transistor, this source-drain electrode links to each other with the lower floor line by contact hole;
6) deposit one deck passivation layer of ultraviolet light thoroughly, and photoetching and etching provide lead terminal.
7, preparation method as claimed in claim 6 is characterized in that, the method peeled off is taked in the processing of the figure of the gate electrode film of described step 1).
8, preparation method as claimed in claim 6 is characterized in that, the method for peeling off is adopted in the figure processing of the semiconductive thin film of described step 3).
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| CN2008101188756A CN101661943B (en) | 2008-08-26 | 2008-08-26 | Monolithic integrated ultraviolet image sensor, pixel units and preparation method thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102446542A (en) * | 2010-09-30 | 2012-05-09 | 海力士半导体有限公司 | Three-dimensional stacked semiconductor integrated circuit |
| TWI580935B (en) * | 2014-05-19 | 2017-05-01 | Idt Europe Gmbh | An ultraviolet sensor having a scattering light suppression effect and a method of measuring ultraviolet rays |
| WO2017190392A1 (en) * | 2016-05-05 | 2017-11-09 | 李成 | Single-chip integrated ultraviolet focal planar device and preparation method therefor |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6798033B2 (en) * | 2002-08-27 | 2004-09-28 | E-Phocus, Inc. | Photoconductor-on-active-pixel (POAP) sensor utilizing a multi-layered radiation absorbing structure |
| KR100653691B1 (en) * | 2004-07-16 | 2006-12-04 | 삼성전자주식회사 | Image sensors having a passivation layer exposing an entire surface of at least a main pixel array region and methods of fabricating the same |
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2008
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102446542A (en) * | 2010-09-30 | 2012-05-09 | 海力士半导体有限公司 | Three-dimensional stacked semiconductor integrated circuit |
| CN102446542B (en) * | 2010-09-30 | 2016-02-24 | 海力士半导体有限公司 | three-dimensional stacked semiconductor integrated circuit |
| TWI580935B (en) * | 2014-05-19 | 2017-05-01 | Idt Europe Gmbh | An ultraviolet sensor having a scattering light suppression effect and a method of measuring ultraviolet rays |
| WO2017190392A1 (en) * | 2016-05-05 | 2017-11-09 | 李成 | Single-chip integrated ultraviolet focal planar device and preparation method therefor |
| CN107346774A (en) * | 2016-05-05 | 2017-11-14 | 上海芯晨科技有限公司 | A kind of single chip integrated ultraviolet FPA and preparation method thereof |
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