EP1405351A2 - Back-illuminated msm module - Google Patents

Back-illuminated msm module

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Publication number
EP1405351A2
EP1405351A2 EP02747215A EP02747215A EP1405351A2 EP 1405351 A2 EP1405351 A2 EP 1405351A2 EP 02747215 A EP02747215 A EP 02747215A EP 02747215 A EP02747215 A EP 02747215A EP 1405351 A2 EP1405351 A2 EP 1405351A2
Authority
EP
European Patent Office
Prior art keywords
msm
electrodes
substrate
layer
pair
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02747215A
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German (de)
French (fr)
Inventor
Peter Gulden
Martin Vossiek
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PMDtechnologies AG
Original Assignee
PMDtechnologies AG
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Filing date
Publication date
Application filed by PMDtechnologies AG filed Critical PMDtechnologies AG
Publication of EP1405351A2 publication Critical patent/EP1405351A2/en
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
    • H01L31/10—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors characterised by potential barriers, e.g. phototransistors
    • H01L31/101—Devices sensitive to infrared, visible or ultraviolet radiation
    • H01L31/102—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier
    • H01L31/108—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier the potential barrier being of the Schottky type
    • H01L31/1085—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier the potential barrier being of the Schottky type the devices being of the Metal-Semiconductor-Metal [MSM] Schottky barrier type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H01L31/184—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof the active layers comprising only AIIIBV compounds, e.g. GaAs, InP
    • H01L31/1852—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof the active layers comprising only AIIIBV compounds, e.g. GaAs, InP comprising a growth substrate not being an AIIIBV compound
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/544—Solar cells from Group III-V materials
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the invention relates to a back-irradiated ("back-illuminated") MSM element as an electro-optical mixer, a corresponding MSM array and a method for producing the MSM element.
  • back-illuminated back-irradiated
  • MSM metal-semiconductor-metal
  • FIMSM front-illuminated MSM
  • the electrodes used cover parts of the light-sensitive semiconductor, which reduces the sensitivity of the MSM element;
  • the MSM element Since the electrodes lie on the illuminated surface, the MSM element must either be contacted from there either by means of so-called “wirebonds", which makes connecting lines necessary, or expensive vias have to be routed to the underside of the semiconductor;
  • BIMSM Back II-luminated MSM
  • the BIMSM element is not the side with the metallization or the electrodes that is illuminated, but the back (Kim, Grie et al. 1992). This avoids covering the photosensitive semiconductor on the illumination side, and the BIMSM element can be contacted directly on the metallized side, for example by means of a flip-chip technology.
  • BIMSM elements still have some problems: the semiconductor must be very thin, which is why it has to be thinned out, which is complex and expensive and causes problems in handling;
  • the MSM element is backlit (BIMSM) and has at least one substrate, at least one above, e.g. B. directly thereon, attached pair of electrodes, and at least one photosensitive layer in turn attached thereon, e.g. B. a semiconductor layer.
  • the monolithic structure can e.g. B. happen in particular by coating. However, additional parts can also be monolithically connected to it, e.g. B. a passivation layer, an intermediate insulating layer or contacts.
  • the monolithic structure of the BIMSM element eliminates the previously required connection technology, e.g. B. attaching wirebonds, which increases reliability and smaller structures with higher degree of integration are made possible. The difficult and costly handling and post-processing of the semiconductor layer, eg. B.
  • the MSM element can be manufactured in one production run using standard processes. This also applies to MSM arrays with several MSM elements or units or also for larger MSM modules in which other elements are also applied to the substrate, e.g. B. evaluation electronics.
  • the MSM element can be used as an electro-optical mixer, at least one electrode of the pair of electrodes being able to couple in a modulation voltage and at least one electrode of the pair of electrodes being able to couple out a mixed product; the choice of the electrode is not restricted: it can e.g. B. be the same electrode or both electrodes can be used for coupling and / or decoupling, z. B. using a suitable filter or mixer.
  • the photosensitive layer is coated with a passivation layer on its irradiable surface. It is also favorable if an insulating layer is present between the substrate and electrodes, in particular using vias through the insulating layer for the electrical connection of the substrate and the electrode structure. It is also advantageous if, on the side of the light-sensitive layer facing away from the irradiable surface, a reflective layer, e.g. B. a metal film is attached.
  • an electronic component in particular an ASIC manufactured in VLSI technology, is integrated in the substrate of the BIMSM element. It is advantageous if the light-sensitive layer is integrated in crystalline form in the electronic component, in particular if the base material of the substrate and light-sensitive layer is the same, advantageously Si.
  • the photosensitive layer is applied as an amorphous thin film. It can also be advantageous if the substrate consists of an electrically insulating material, in particular glass or ceramic, in particular if additional building blocks, eg. B. a separate evaluation unit or pixel electronics, are (modular design), the z. B. have been applied by means of flip-chip technology.
  • additional building blocks eg. B. a separate evaluation unit or pixel electronics, are (modular design), the z. B. have been applied by means of flip-chip technology.
  • the layer thicknesses of the BIMSM element are selected such that the transmissivity of the interface to the light-sensitive layer is wavelength-selective, in particular if the layer thicknesses correspond to a quarter of the preferred wavelength or one or a multiple thereof.
  • an MSM array which has at least two MSM elements (pixels), in particular if these MSM elements are connected to a common modulation electronics and / or which has at least one integrated evaluation circuit.
  • An MSM array is preferred in which a read-out circuit for individual operation as a photoelectric mixer is integrated in each pixel individually.
  • the frequency-dependent amplification is selected such that an upstream filter can be dispensed with.
  • the MSM element can be produced, preferably using VLSI (Very Large Scale Integrated) technology, in such a way that the pair of electrodes, optionally with an intermediate layer or embedded in a layer, is applied coated on the substrate, and at least the pair of electrodes is coated in such a way that the photosensitive layer forms thereon.
  • VLSI Very Large Scale Integrated
  • Figure 1 shows a FIMSM element according to the prior art in oblique view (Fig. La), side view (Fig. Lb) and top view (Fig. Lc);
  • Figure 2 shows a sandwich BIMSM module in side view (Fig. 2a) and top view (Fig. 2b) and in side view with elongated electrodes (Fig. 2b);
  • Figure 3 shows another sandwich BIMSM module;
  • FIG. 4 shows a further sandwich BIMSM module;
  • Figure 5 shows an MSM array;
  • Figure 6 shows an MSM system.
  • FIG. 1 shows a sketch of a front-illuminated MSM element (FIMSM), which is continued on the right-hand side, as the points symbolize it.
  • FIMSM front-illuminated MSM element
  • the front-illuminated MSM element is produced by applying a metal layer to a non-or weakly doped semiconductor substrate ST1 and structuring it in a finger shape.
  • the fingers or finger electrodes ST2 are connected in opposite directions and are operated with a differential voltage as a bias. If one modulates this differential voltage and simultaneously illuminates the MSM element with intensity-modulated light ST3 of the same modulation frequency, a phase difference can then be determined from the mixed product.
  • This FIMSM element is connected to other components, e.g. B. an electronic, connected with methods of connection technology, for. B. using wirebonds.
  • the photosensitive semiconductor substrate ST1 When used as a BIMSM element, the photosensitive semiconductor substrate ST1 has so far been thinned out in a subsequent process step, which makes handling difficult.
  • the contact with other components can in this case, for. B. also done by means of a flip-chip method.
  • FIG. 2 shows a BIMSM element (“sandwich BIMSM element”) produced monolithically as a layer composite.
  • an electronic component 1 On a substrate in the form of an electronic component 1, here: one ASICs are a first insulating layer 6 and a metallic (finger) pair of electrodes 2 thereon using thin-film technology, preferably using standard VLSI processes according to Baker, JR; Li, HW et al 1998 applied.
  • the electronic component 1 contains, for example, a readout and further processing unit 7 or, for. B. when configured in an MSM array MAR, a pixel electronics 8.
  • the pair of electrodes 2 is embedded in a second insulating layer 6 '. 2b shows a top view of the geometry of the electrode pair 2 with the position of the vias 5.
  • the semiconductor thin layer is coated with a passivation layer 4.
  • through-contacts ("vias") 5 are guided through the first insulating layer 6, the position of which can be adapted to the respective application, see FIG. 2b.
  • the pair of electrodes 2 can also be connected via lateral leads 5 ', see e.g. B. Fig. 3b.
  • the first insulating layer 6 can also be omitted if the electrodes 2 can be accommodated on the electronic component 1 without them; however, it is favorable for reducing interference and for improving field propagation.
  • the material of the second insulating layer 6 ' which is also optional, is preferably the same as that of the first insulating layer 6, that is to say embedded in it.
  • process engineering see e.g. B. Böhm, Blecher et al. 1998th
  • FIG. 2a shows a sandwich BIMSM element in which the electrodes 2 lie within the second insulating layer 6 ', as a result of which the light-sensitive layer 3 can be applied very easily and does not have to be reworked, e.g. B. must be thinned.
  • the electrodes 2 ' can also protrude into the light-sensitive layer 3, as shown in FIG. 2c.
  • Materials are preferably selected that can be used well in standard CMOS technology, eg. B. Pd, Au and other noble metals for the electrode structure 2 and the vias 5 and Si0 2 for the insulating layers 6,6 '.
  • the material of the photosensitive layer 3 is not limited to semiconductors, but can e.g. B. also include polymers that show the photoelectric effect. Suitable light-sensitive semiconductor layers include amorphous silicon, possibly with a doping.
  • the optional passivation layer 4 is preferably transparent.
  • the electronic component 1 is preferably constructed using silicon technology, but is not restricted to this. By using several superimposed thin layers, other effects, e.g. B. the avalanche or tunnel effect can be used.
  • the light-sensitive layer 3 consists of the same semiconductor base material as the electronic component 1, advantageously Si.
  • the Si in the light-sensitive layer 3 can be suitably doped, see Sze 1969; Pierret 1996; Sze 1998.
  • the application of the first insulating layer 6 has been dispensed with, ie the photosensitive layer 3 lies directly on the electronic component 1.
  • the electronic component 1 usually consists of several layers, e.g. B. semiconductor / metal / insulator, can no longer be distinguished in this embodiment between the electronic component 1 and the other MSM structures, the MSM structure can be seen as part of the electronic component 1.
  • the MSM element M can thus also be understood such that an electronic component 1, in particular an ASIC produced using VLSI technology, is integrated in the substrate. This procedure is cheaper than using different semiconductors for the electronic component " ! And the photosensitive layer 3, since one process step is omitted.
  • the electrodes 2 are either under the photosensitive layer 3, see FIG. 3a, or embedded within the photosensitive layer 3, see FIG. 3c.
  • the materials and processes known from CMOS cameras are preferably used.
  • the electrodes 2 are produced by suitable structuring of the metal layers within the ASIC.
  • the coupling out of the mixed signal and the coupling in of the modulation can either be carried out analogously to the previous exemplary embodiment by connecting to lower-lying metallization layers, or laterally by means of leads which produce a connection to parts lying outside in the same layer.
  • the coupling signal can be decoupled either within the electronic component 1 or by means of externally attached filter circuits.
  • the electronic component 1, here: the ASIC can itself either be contacted again from the side by means of conventional wirebonds or, if the pads are arranged appropriately under the ASIC, using flip-chip technology, for. B. Fine pitch flip chip technology.
  • FIG. 4 shows a sandwich BIMSM structure M ', in which no semiconductor substrate is used, but rather the electrodes 2 directly on an insulating substrate 1', in particular a ceramic or glass substrate, see, for example, BL-H. Laih 1999, are applied and then coated with one or more photosensitive semiconductor layers 3.
  • the electrodes 2 can either be flat or protrude into the light-sensitive layer 3 to improve the field distribution.
  • the Separation between mixed signal and modulation signal by means of a discrete filter 11 implemented on the substrate.
  • the values can then be recorded directly from the external periphery, eg. B. in an applied to the substrate 1 'integrated circuit IC, here a readout and / or further processing unit 7, stored and / or processed.
  • the read-out circuit 7 and further electronics can be implemented directly modularly on the substrate 1 ', for. B. in flip-chip technology.
  • the combination of electrodes 2 and light-sensitive layer 3 can be selected such that either a Schottky or an ohmic transition is formed.
  • doped n-i-n junctions can also be used. For the above-mentioned transitions see among others Sze 1969; Pierret 1996; Sze 1998.
  • the thin film combinations mentioned in Fischer 1996 are preferably used for the layers 2, 3, since this is compatible with standard processes.
  • a preferred embodiment consists in the layer thicknesses, for. B. to choose the thicknesses a, b, c in FIG. 3 so that they correspond to a fraction or a multiple of the fraction of the incident wavelength and the fraction is chosen such that the transition from air-photosensitive layer 3 or , Passivation layer 4 - photosensitive layer 3 or air - photosensitive layer 3 is wavelength selective.
  • Preferred fractions are a quarter and odd multiples thereof. Either the z. B. entire layer c, or part a over the electrodes, the electrode thickness ba and part cb under the electrodes are chosen accordingly.
  • the sensitivity can generally be increased in that after the photosensitive layer 3 there is a specular transition to the next layer, as a result of which non-absorbed light is reflected back into the photosensitive layer 3, where it then still absorbs. This is also advantageous for realizing a thinner layer.
  • the reflection at the end of the light-sensitive layer can be realized, inter alia, by a different refractive index of the next semiconductor layer or by drawing in a thin metal layer 9.
  • a transparent passivation layer 4 can be applied to the light-sensitive layer 3, e.g. B. to prevent surface oxidation or abrasion.
  • This passivation layer 4 can also be designed as an antireflection layer or, in connection with the transition between the photosensitive layer 3 and the layer below it, form a Fabry-Perot or Bragg resonator, see Kowalsky and Prank 1993; Litvin, Burm et al. 1993) and (Bassous, Halbout et al. 1994.
  • Suitable operating circuits for the use of FIMSM elements as electro-optical mixers can be found in (Ruff, Bruno et al. 2000; Shen, Stead et al. 2000). In principle, one can differentiate between one-sided and two-sided modulation. In a conventional circuit, the voltage on one of the two finger structures is modulated with a certain frequency. The other finger is placed on a constant bias voltage, and the mixed signal is coupled out by means of a filter. Such a read-out circuit is advantageously also in every pixel Ml, ..., Mmn of the sandwich BIMSM structure integrated. The frequency dependent gain ⁇ of the integrated amplifier is preferably selected such that an upstream filter can be omitted. A particular advantage of this arrangement is that there is no need to decouple the modulated electrodes 2 of all pixels Ml,..., Mmn, ie they are simply connected and led directly to the contact.
  • FIG. 5 shows a BIMSM array MAR with a plurality of (mxn) MSM elements Ml, M2, Mn + 1, Mn + 2, ... (pixels), which are continued in two directions n / m, as by the dots and arrows indicated.
  • driver 10 for the modulation voltage z. B. in each pixel Ml, M2, ..., Mn + l, Mn + 2, ..., Mnm (indicated by the triangles), or when arranged in the array MAR at the beginning of each array line 1 ... n or 1 ... m.
  • both electrodes of the respective pair of electrodes 2 are modulated in a complementary manner, and the mixed product is coupled out at each of the two electrodes 2.
  • the modulation signal is fed in via a common conductor 14;
  • the pixels Ml, M2, ..., Mn + 1, Mn + 2, ..., Mnm are connected via side contacts 5 'to an electronic signal filter (not shown) which supplies the bias and filters an output signal and amplifies and possibly stores the signal and includes addressing logic.
  • Such a circuit is preferably integrated into each pixel M1, M2, Mn + 1, Mn + 2, Mnm.
  • the problem of decoupling the individual pixels Ml, M2, ..., Mn + 1, Mn + 2, ..., Mnm can be solved either by capacitive coupling of the modulation signals of each pixel Ml, M2, Mn + 1, Mn + 2, Mnm or by integrating an amplifier 12 into each pixel Pixel Ml, M2, ..., Mn + 1, Mn + 2, ..., Mnm.
  • the readout then takes place behind the amplifier 12, with either a filter 11 or an adapted readout amplifier or a readout unit 7 being integrated as before.
  • the reading of the corresponding signals can, for. B. according to Böhm, Blecher et al. 1998 either as current or as voltage selection.
  • the readout circuits 7, storage options and addressing methods of the pixel electronics 8 are preferably implemented in each pixel of pixels Ml, M2, ..., Mn + 1, Mn + 2, ..., Mnm.
  • processes with high dynamics e.g. B. according to Lule, Keller et al. 1999.
  • methods and arrangements are favorably used, in particular for difference formation according to Schwarte 1997; Rake integrated in every pixel Ml, M2, Mn + 1, Mn + 2, Mnm in 1997.
  • MSM elements into which sigma-delta converters are integrated are also inexpensive, see analogously to this Gulden, Vossiek et al. 2000 for PMDs.
  • the "sandwich MSM” mixers can then be operated using the modulation methods described for PMD structures, e.g. IQ, Pseu- do Noise (Schwarte 1997; Schwarte 1997), 2-Frequency, FSCW, FMCW (Gulden, Vossiek et al. 2000). Furthermore, an electro-optical control loop, for example for distance measurement, can be implemented. B. Gulden, Vossiek et al. 2000th
  • FIG. 6 shows a system for distance measurement using a monolithic MSM array MAR.
  • the system has a light source Q for emitting modulated light, e.g. B. a laser diode or an LED, the output optics TO is connected downstream.
  • the system further comprises a receiver optics RO for bundling the incident modulated light ST3, which then falls on the MSM array MAR.
  • the incident light can be bundled by using optics and lenses already used for CMOS sensors or PMD systems, see Tai, Schwarte et al. 2000th
  • the MSM array MAR can be controlled by means of a readout and / or further processing unit 7, for example a computer, a digital signal processor, a microprocessor or an FPGA.
  • the readout and / or further processing unit 7 receives data SIG3 from the MSM array MAR and supplies it with a control signal SIG2.
  • it also outputs measurement data OUT, e.g. B. data for distance measurement, provides a control signal SIG1 for the pixel electronics 8 (here: modulation electronics), which in turn controls the MSM array MAR and the light source Q.
  • Such a system can e.g. to monitor the seating position in the car (Mengel and Doemens 1997; Doemens and Mengel 1998).
  • a similar system can also be used to monitor the exterior of the car (Schwarte, Buxbaum et al. 2000).
  • Preferred implementations of these systems use infrared light so as not to disturb the driver.
  • VDE 1994 the standards for eye safety
  • Suitable materials according to the state of the art include in (Sze 1969; Pierret 1996; Sze 1998).
  • Preferred mounting positions are directly behind the windshield or in the existing headlights.
  • Comparable systems with direct current reading can be used according to the invention as phase detectors in electro-optical control loops, for example in a PLL, as phase detectors for clock synchronization or as demodulators in, for example, CDMA or QPSK communication systems (Buxbaum, Schwarte et al. 2000). Baker, JR, Li, HW et al. (1998). CMOS. Circuit design, layout, and simulation; IEEE 1998 Bassous, E., J.-M. Halbout, et al. (1994). High Speed Silicon-Based Lateral Junction Photodetectors Having Recessed Electrodes and Thick Oxide to Reduce Fringing Fields. 5,525,828. United States, International Business Machines Corporation: 28. Boehm, M., F.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)

Abstract

The invention relates to a BIMSM element (M,M'), in which at least the substrate (1,1'), the electrode pair (2) and the photosensitive layer (3) are combined in a monolithic structure. According to the invention, at least one electrode of the electrode pair (2) can be used to induce a modulation voltage, at least one electrode of the electrode pair (2) can be used to decouple a mixed product and the MSM element (M,M') can be used as an electro-optical mixer. The invention differs from known MSM elements in that the photosensitive layer (3) is deposited on the electrodes.

Description

Beschreibungdescription
Rückseitenbestrahlbares MSM-ModulBack-irradiable MSM module
Die Erfindung betrifft ein rückseitenbestrahlbares ("back- illu inated") MSM- Element als elektrooptischen Mischer, ein entsprechendes MSM-Array und ein Verfahren zur Herstellung des MSM-Elementes .The invention relates to a back-irradiated ("back-illuminated") MSM element as an electro-optical mixer, a corresponding MSM array and a method for producing the MSM element.
Zur Bestimmung der Phasendifferenz zwischen einer einfallen- den elektromagnetischen Welle und einer entsprechenden Modulationsspannung sind elektrooptische Mischer bekannt, auf der Grundlage von Metall-Halbleiter-Metall- ("MSM" = Metal- Serαiconductor-Metal) Strukturen bekannt, siehe MacDonald and Swekla 1990; Liu and MacDonald 1993; Ruff, Bruno et al. 2000; Shen, Stead et al. 2000).To determine the phase difference between an incident electromagnetic wave and a corresponding modulation voltage, electro-optical mixers are known, based on metal-semiconductor-metal ("MSM" = metal-semiconductor metal) structures, see MacDonald and Swekla 1990; Liu and MacDonald 1993; Ruff, Bruno et al. 2000; Shen, Stead et al. 2000).
Bisher werden Front-Illuminated-MSM- (FIMSM-) Elemente als e- lektrooptische Mischer eingesetzt, siehe Figur 1, welche einige Nachteile aufweisen:So far, front-illuminated MSM (FIMSM) elements have been used as electro-optical mixers, see FIG. 1, which have some disadvantages:
- die verwendeten Elektroden bedecken Teile des licht- empfindlichen Halbleiters, wodurch die Sensitivität des MSM-Elements reduziert wird;- The electrodes used cover parts of the light-sensitive semiconductor, which reduces the sensitivity of the MSM element;
- da die Elektroden auf der beleuchteten Oberfläche liegen, uss das MSM-Element entweder von dort entweder mittels sogenannter " Wirebonds" kontaktiert werden, wodurch Ver- bindungsleitungen notwendig werden, oder es müssen kostspielige Vias bis auf die Halbleiterunterseite geführt werden;- Since the electrodes lie on the illuminated surface, the MSM element must either be contacted from there either by means of so-called "wirebonds", which makes connecting lines necessary, or expensive vias have to be routed to the underside of the semiconductor;
- das Feld der Elektroden reicht nur bis zu einer begrenzten Tiefe in den Halbleiter hinein. Dadurch unterliegen in relativ großer Tiefe generierte Photoelektronen nur noch sehr schwachen Feldstärken, oder es müssen spezielle, teure Halbleitermaterialien mit hoher Absorption wie z.B. GaAs eingesetzt werden;- The field of the electrodes only extends to a limited depth into the semiconductor. As a result, photoelectrons generated at a relatively great depth are only subject to very weak field strengths, or special, expensive semiconductor materials with high absorption, e.g. GaAs are used;
- die Integration weiterer Funktionen im Halbleiter ist eingeschränkt bzw. sehr komplex. Als reiner Photodetektor wird auch ein sogenanntes "Back II- luminated MSM" (BIMSM) -Element eingesetzt. Beim BIMSM-Element wird nicht die Seite mit der Metallisierung bzw. mit den E- lektroden beleuchtet, sondern die Rückseite (Kim, Grie et al. 1992). Dadurch wird die Abdeckung des photoempfindlichen Halbleiters auf der Beleuchtungsseite vermieden, und das BIMSM-Element kann direkt auf der metallisierten Seite kontaktiert werden, z.B. mittels einer Flip-Chip-Technik.- The integration of other functions in the semiconductor is limited or very complex. A so-called "Back II-luminated MSM" (BIMSM) element is also used as a pure photodetector. With the BIMSM element, it is not the side with the metallization or the electrodes that is illuminated, but the back (Kim, Grie et al. 1992). This avoids covering the photosensitive semiconductor on the illumination side, and the BIMSM element can be contacted directly on the metallized side, for example by means of a flip-chip technology.
Allerdings weisen BIMSM-Elemente noch einige Probleme auf: - der Halbleiter muss sehr dünn sein, weshalb er ausgedünnt werden muss, was aufwendig und teuer ist und Probleme bei der Handhabung verursacht;However, BIMSM elements still have some problems: the semiconductor must be very thin, which is why it has to be thinned out, which is complex and expensive and causes problems in handling;
- eine weitere Integration von Ausleseelektronik und Anwen- dungschaltungen ist nur sehr schwierig möglich. Es ist die Aufgabe der vorliegenden Erfindung, eine BIMSM- Struktur bereitzustellen, welche zuverlässig arbeitet, eine einfach Integration der Auslesefunktionen ermöglicht und vergleichsweise einfach handzuhaben und preiswert und flexibel herstellbar ist. Diese Aufgabe wird mittels eines MSM-Elements gemäß Patentanspruch 1, eines MSM-Arrays nach Anspruch 9 sowie eines Herstellungsverfahrens gemäß Anspruch 12 gelöst.- Further integration of readout electronics and application circuits is very difficult. It is the object of the present invention to provide a BIMSM structure which works reliably, enables simple integration of the readout functions and is comparatively simple to use and can be produced inexpensively and flexibly. This object is achieved by means of an MSM element according to claim 1, an MSM array according to claim 9 and a manufacturing method according to claim 12.
Das MSM-Element ist rückseitenbeleuchtbar (BIMSM) und weist mindestens ein Substrat, mindestens ein oberhalb, z. B. direkt darauf, angebrachtes Elektrodenpaar, und mindestens eine wiederum darauf angebrachte lichtempfindliche Schicht, z. B. eine Halbleiterschicht, auf. Der monolithische Aufbau kann z. B. insbesondere durch Beschichtung geschehen. Es können aber auch noch zusätzliche Teile damit monolithisch verbunden sein wie z. B. eine Passivierungsschicht, eine zwischenliegende Isolierschicht oder Kontaktierungen. Durch den monolithischen Aufbau des BIMSM-Elements entfällt die bisher notwendige Verbindungstechnik, z. B. das Anbringen von Wirebonds, wodurch sich die Zuverlässigkeit erhöht und kleinere Strukturen mit höherem Integrationsgrad ermöglicht werden. Auch entfällt die schwierige und kostentreibende Handhabung und Nachbearbeitung der Halbleiterschicht, z. B. zur Ausdünnung. Das MSM-Element kann in vielen Fällen durch Standardprozesse in einem Her- stellungsgang gefertigt werden. Dies gilt auch für MSM-Arrays mit mehreren MSM-Elementen oder -Einheiten oder auch für größere MSM-Module, bei denen auf dem Substrat auch andere Elemente aufgebracht sind, z. B. eine Auswerteelektronik. Das MSM-Element ist als elektrooptischer Mischer einsetzbar, wo- bei mindestens eine Elektrode des Elektrodenpaars zur Einkop- pelung einer Modulationsspannung und mindestens eine Elektrode des Elektrodenpaars zur Auskopplung eines Mischproduktes verwendbar ist; die Wahl der Elektrode ist nicht eingeschränkt: es kann z. B. dieselbe Elektrode sein oder es kön- nen beide Elektroden zur Ein- und/oder Auskopplung eingesetzt werden, z. B. unter Verwendung eines geeigneten Filters oder Mischers .The MSM element is backlit (BIMSM) and has at least one substrate, at least one above, e.g. B. directly thereon, attached pair of electrodes, and at least one photosensitive layer in turn attached thereon, e.g. B. a semiconductor layer. The monolithic structure can e.g. B. happen in particular by coating. However, additional parts can also be monolithically connected to it, e.g. B. a passivation layer, an intermediate insulating layer or contacts. The monolithic structure of the BIMSM element eliminates the previously required connection technology, e.g. B. attaching wirebonds, which increases reliability and smaller structures with higher degree of integration are made possible. The difficult and costly handling and post-processing of the semiconductor layer, eg. B. for thinning. In many cases, the MSM element can be manufactured in one production run using standard processes. This also applies to MSM arrays with several MSM elements or units or also for larger MSM modules in which other elements are also applied to the substrate, e.g. B. evaluation electronics. The MSM element can be used as an electro-optical mixer, at least one electrode of the pair of electrodes being able to couple in a modulation voltage and at least one electrode of the pair of electrodes being able to couple out a mixed product; the choice of the electrode is not restricted: it can e.g. B. be the same electrode or both electrodes can be used for coupling and / or decoupling, z. B. using a suitable filter or mixer.
Es ist vorteilhaft, falls die lichtempfindliche Schicht auf ihrer bestrahlbaren Fläche mit einer Passivierungsschicht beschichtet ist. Es ist auch günstig, wenn zwischen Substrat und Elektroden eine Isolierschicht vorhanden ist, insbesondere unter Verwendung von Vias durch die Isolierschicht zur e- lektrischen Verbindung von Substrat und Elektrodenstruktur. Auch ist es günstig, falls auf der der bestrahlbaren Fläche abgewandten Seite der lichtempfindlichen Schicht eine spiegelnde Schicht, z. B. ein Metallfilm, angebracht ist.It is advantageous if the photosensitive layer is coated with a passivation layer on its irradiable surface. It is also favorable if an insulating layer is present between the substrate and electrodes, in particular using vias through the insulating layer for the electrical connection of the substrate and the electrode structure. It is also advantageous if, on the side of the light-sensitive layer facing away from the irradiable surface, a reflective layer, e.g. B. a metal film is attached.
Es ist weiterhin günstig, falls in das Substrat des BIMSM- Elements ein elektronischer Baustein, insbesondere ein in VLSI-Technik gefertigter ASIC, integriert ist. Es ist dabei günstig, wenn die lichtempfindliche Schicht kristallin im e- lektronischen Baustein integriert ist, insbesondere, falls das Grundmaterial von Substrat und lichtempfindlicher Schicht das gleiche ist, günstigerweise Si.It is furthermore favorable if an electronic component, in particular an ASIC manufactured in VLSI technology, is integrated in the substrate of the BIMSM element. It is advantageous if the light-sensitive layer is integrated in crystalline form in the electronic component, in particular if the base material of the substrate and light-sensitive layer is the same, advantageously Si.
Es ist vorteilhaft, wenn die photoempfindliche Schicht als amorpher Dünnfilm aufgebracht ist. Auch kann es vorteilhaft sein, falls das Substrat aus einem elektrisch isolierenden Material besteht, insbesondere Glas oder Keramik, insbesondere, falls sich auf dem Substrat zu- sätzliche Bausteine, z. B. eine separate Auswerteeinheit oder eine Pixelelektronik , befinden (Modulbauweise), die z. B. mittels Flip-Chip-Technik aufgebracht worden sind.It is advantageous if the photosensitive layer is applied as an amorphous thin film. It can also be advantageous if the substrate consists of an electrically insulating material, in particular glass or ceramic, in particular if additional building blocks, eg. B. a separate evaluation unit or pixel electronics, are (modular design), the z. B. have been applied by means of flip-chip technology.
Es ist weiterhin vorteilhaft, wenn die Schichtdicken des BIMSM-Elernents so gewählt sind, dass die Durchlässigkeit der Grenzfläche zur lichtempfindlichen Schicht wellenlängenselektiv ist, insbesondere falls die Schichtdicken einem Viertel der bevorzugten Wellenlänge oder einem oder einem Vielfachen hiervon entsprechen.It is also advantageous if the layer thicknesses of the BIMSM element are selected such that the transmissivity of the interface to the light-sensitive layer is wavelength-selective, in particular if the layer thicknesses correspond to a quarter of the preferred wavelength or one or a multiple thereof.
Erfinderisch ist ebenfalls ein MSM-Array, das mindestens zwei MSM-Elemente (Pixel) aufweist, insbesondere falls diese MSM- Elemente an eine gemeinsame Modulationselektronik angeschlossen sind und / oder das mindestens eine integrierte Auswerte- Schaltung aufweist. Dabei wird ein MSM-Array bevorzugt, bei dem in jedem Pixel einzeln eine Ausleseschaltung zum Einzelbetrieb als photoelektrischer Mischer integriert ist.Also inventive is an MSM array which has at least two MSM elements (pixels), in particular if these MSM elements are connected to a common modulation electronics and / or which has at least one integrated evaluation circuit. An MSM array is preferred in which a read-out circuit for individual operation as a photoelectric mixer is integrated in each pixel individually.
Es ist zum vereinfachten Aufbau vorteilhaft, wenn die fre- quenzabhängige Verstärkung so gewählt ist, dass auf einen vorgeschalteten Filter verzichtet werden kann.For a simplified structure, it is advantageous if the frequency-dependent amplification is selected such that an upstream filter can be dispensed with.
Das MSM-Element kann, vorzugsweise in VLSI (Very Large Scale Integrated) -Technik, so hergestellt werden, dass das Elektro- denpaar, ggf. mit einer Zwischenschicht oder in eine Schicht eingebettet, auf dem Substrat beschichtet aufgebracht wird, und mindestens das Elektrodenpaar derart beschichtet wird, das sich darauf die lichtempfindliche Schicht bildet.The MSM element can be produced, preferably using VLSI (Very Large Scale Integrated) technology, in such a way that the pair of electrodes, optionally with an intermediate layer or embedded in a layer, is applied coated on the substrate, and at least the pair of electrodes is coated in such a way that the photosensitive layer forms thereon.
In den folgenden Ausführungsbeispielen wird die Erfindung schematisch näher dargestellt: Figur 1 zeigt ein FIMSM-Element nach dem Stand der Technik in Schrägansicht (Fig. la) , Seitenansicht (Fig. lb) und Draufsicht (Fig. lc) ; Figur 2 zeigt ein Sandwich-BIMSM-Modul in Seitenansicht (Fig. 2a) und Aufsicht (Fig. 2b) sowie in Seitenansicht mit verlängerten Elektroden (Fig. 2b) ; Figur 3 zeigt ein weiteres Sandwich-BIMSM-Modul; Figur 4 zeigt ein weiteres Sandwich-BIMSM-Modul; Figur 5 zeigt ein MSM-Array; Figur 6 zeigt ein MSM-System.The invention is illustrated schematically in more detail in the following exemplary embodiments: Figure 1 shows a FIMSM element according to the prior art in oblique view (Fig. La), side view (Fig. Lb) and top view (Fig. Lc); Figure 2 shows a sandwich BIMSM module in side view (Fig. 2a) and top view (Fig. 2b) and in side view with elongated electrodes (Fig. 2b); Figure 3 shows another sandwich BIMSM module; FIG. 4 shows a further sandwich BIMSM module; Figure 5 shows an MSM array; Figure 6 shows an MSM system.
Figur 1 zeigt skizzenhaft ein Front-Illuminated-MSM-Element (FIMSM) , welches auf der rechten Seite, wie die Punkte es sy- bolisieren, weitergeführt wird.FIG. 1 shows a sketch of a front-illuminated MSM element (FIMSM), which is continued on the right-hand side, as the points symbolize it.
Das Front-Illuminated-MSM-Element wird hergestellt, indem auf einem nicht oder schwach dotierten Halbleitersubstrat ST1 eine Metallschicht aufgebracht und fingerförmig strukturiert wird. Die Finger bzw. Fingerelektroden ST2 sind gegenläufig miteinander verbunden und werden mit einer Differenzspannung als Bias betrieben. Moduliert man diese DifferenzSpannung und beleuchtet gleichzeitig das MSM-Element mit intensitätsmodu- liertem Licht ST3 gleicher Modulationsfrequenz, ist anschließend aus dem Mischprodukt eine Phasendifferenz bestimmbar.The front-illuminated MSM element is produced by applying a metal layer to a non-or weakly doped semiconductor substrate ST1 and structuring it in a finger shape. The fingers or finger electrodes ST2 are connected in opposite directions and are operated with a differential voltage as a bias. If one modulates this differential voltage and simultaneously illuminates the MSM element with intensity-modulated light ST3 of the same modulation frequency, a phase difference can then be determined from the mixed product.
Dieses FIMSM-Element wird über seine Elektroden ST2 an andere Bauteile, z. B. eine Auswerteelektronik, mit Methoden der Verbindungstechnik angeschlossen, z. B. mittels Wirebonds.This FIMSM element is connected to other components, e.g. B. an electronic, connected with methods of connection technology, for. B. using wirebonds.
Bei Verwendung als BIMSM-Element muss bisher nach der Herstellung des photoempfindlichen Halbleitersubstrats ST1 dieses in einem nachgeschalteten Verfahrensschritt ausgedünnt werden, wodurch die Handhabung aufwendig wird. Die Kontaktie- rung mit anderen Bauteilen kann in diesem Fall z. B. auch mittels eines Flip-Chip-Verfahrens geschehen.When used as a BIMSM element, the photosensitive semiconductor substrate ST1 has so far been thinned out in a subsequent process step, which makes handling difficult. The contact with other components can in this case, for. B. also done by means of a flip-chip method.
Figur 2 zeigt ein als Schichtverbund monolithisch hergestelltes BIMSM-Element ( "Sandwich-BIMSM-Element" ) . Auf ein Sub- strat in Form eines elektronischen Bauteils 1, hier-: eines ASICs, sind eine erste Isolierschicht 6 und darauf ein metallisches (Finger-) Elektrodenpaar 2 in Dünnfilmtechnik, bevorzugt mittels Standard-VLSI-Prozessen nach Baker, J.R.; Li, H.W. et al 1998 aufgebracht. Das elektronische Bauteil 1 ent- hält beispielsweise eine Auslese- und Weiterverarbeitungseinheit 7 oder, z. B. bei Konfiguration in einem MSM-Array MAR, eine Pixelelektronik 8. Das Elektrodenpaar 2 ist in eine zweite Isolierschicht 6' eingebettet. Fig. 2b zeigt in Aufsicht die Geometrie des Elektrodenpaars 2 mit Lage der Vias 5. Auf das Elektrodenpaar 2 wiederum ist eine lichtempfindliche Schicht 3, in Form einer Halbleiter-Dünnschicht aus dotiertem amorphen Si aufgebracht. Die Halbleiter-Dünnschicht ist mit einer Passivierungsschicht 4 beschichtet. Zur Ankopp- lung von Elektrodenpaar 2 und elektronischem Bauteil 1 sind durch die erste Isolierschicht 6 punktuell Durchkontaktierun- gen ("Vias") 5 geführt, deren Lage sich an die jeweilige Anwendung anpassen lässt, siehe Fig. 2b. Das Elektrodenpaar 2 kann aber auch über seitliche Zuführungen 5' angeschlossen sein, siehe z. B. Fig. 3b. Die erste Isolierschicht 6 kann auch weggelassen werden, falls die Elektroden 2 sich ohne diese auf dem elektronischen Bauteil 1 unterbringen lassen; sie ist aber günstig zur Reduktion von Störungen und zur verbesserten Feldausbreitung. Das Material der zweiten Isolierschicht 6', welche ebenfalls optional ist, ist vorzugsweise gleich demjenigen der ersten Isolierschicht 6, also in diese eingebettet. Zur Verfahrenstechnik siehe z. B. Böhm, Blecher et al. 1998.FIG. 2 shows a BIMSM element (“sandwich BIMSM element”) produced monolithically as a layer composite. On a substrate in the form of an electronic component 1, here: one ASICs are a first insulating layer 6 and a metallic (finger) pair of electrodes 2 thereon using thin-film technology, preferably using standard VLSI processes according to Baker, JR; Li, HW et al 1998 applied. The electronic component 1 contains, for example, a readout and further processing unit 7 or, for. B. when configured in an MSM array MAR, a pixel electronics 8. The pair of electrodes 2 is embedded in a second insulating layer 6 '. 2b shows a top view of the geometry of the electrode pair 2 with the position of the vias 5. A light-sensitive layer 3, in the form of a semiconductor thin layer made of doped amorphous Si, is in turn applied to the electrode pair 2. The semiconductor thin layer is coated with a passivation layer 4. For coupling the pair of electrodes 2 and the electronic component 1, through-contacts ("vias") 5 are guided through the first insulating layer 6, the position of which can be adapted to the respective application, see FIG. 2b. The pair of electrodes 2 can also be connected via lateral leads 5 ', see e.g. B. Fig. 3b. The first insulating layer 6 can also be omitted if the electrodes 2 can be accommodated on the electronic component 1 without them; however, it is favorable for reducing interference and for improving field propagation. The material of the second insulating layer 6 ', which is also optional, is preferably the same as that of the first insulating layer 6, that is to say embedded in it. For process engineering see e.g. B. Böhm, Blecher et al. 1998th
Der Vorteil dieses Aufbaus liegt in der vielfältigen Ko bina- tionsmöglichkeit unterschiedlicher Materialien, insbesondere der Halbleitermaterialien, und in den Ermöglichung extrem hoher Füllfaktoren.The advantage of this design lies in the wide range of possible combinations of different materials, in particular semiconductor materials, and in the fact that extremely high fill factors are possible.
In Fig. 2a ist ein Sandwich-BIMSM-Element gezeigt, bei dem die Elektroden 2 innerhalb der zweiten Isolierschicht 6' liegen, wodurch die lichtempfindliche Schicht 3 sehr einfach aufgetragen werden kann und nicht nachbearbeitet, z. B. ausgedünnt, werden muss. Zur Verbesserung der Feldverteilung und somit zur Erhöhung des Modulationsgrades können die Elektroden 2' auch in die lichtempfindliche Schicht 3 hineinragen, wie in Fig. 2c gezeigt.2a shows a sandwich BIMSM element in which the electrodes 2 lie within the second insulating layer 6 ', as a result of which the light-sensitive layer 3 can be applied very easily and does not have to be reworked, e.g. B. must be thinned. To improve field distribution and thus to increase the degree of modulation, the electrodes 2 'can also protrude into the light-sensitive layer 3, as shown in FIG. 2c.
Bevorzugt werden Materialien gewählt, die in Standard-CMOS- Technik gut verwendbar sind, z. B. Pd, Au und andere Edelmetalle für die Elektrodenstruktur 2 und die Vias 5 sowie Si02 für die Isolierschichten 6,6'. Das Material der lichtempfindlichen Schicht 3 ist nicht auf Halbleiter beschränkt sondern kann z. B. auch Polymere umfassen, welche den photoelektri- sehen Effekt zeigen. Als lichtempfindliche Halbleiterschicht eignet sich unter anderem amorphes Silizium, gegebenenfalls mit einer Dotierung. Die optionale Passivierungsschicht 4 ist bevorzugt durchsichtig. Das elektronische Bauteil 1 ist bevorzugt in Siliziumtechnik aufgebaut, aber nicht darauf ein- geschränkt. Durch Verwendung mehrerer übereinanderliegender Dünnschichten können weitere Effekte, z. B. der Avalanche- oder der Tunneleffekt, genutzt werden.Materials are preferably selected that can be used well in standard CMOS technology, eg. B. Pd, Au and other noble metals for the electrode structure 2 and the vias 5 and Si0 2 for the insulating layers 6,6 '. The material of the photosensitive layer 3 is not limited to semiconductors, but can e.g. B. also include polymers that show the photoelectric effect. Suitable light-sensitive semiconductor layers include amorphous silicon, possibly with a doping. The optional passivation layer 4 is preferably transparent. The electronic component 1 is preferably constructed using silicon technology, but is not restricted to this. By using several superimposed thin layers, other effects, e.g. B. the avalanche or tunnel effect can be used.
In Figur 3 besteht die lichtempfindliche Schicht 3 aus dem- selben Halbleiter-Grundmaterial wie das elektronische Bauteil 1, günstigerweise Si. In der lichtempfindlichen Schicht 3 kann das Si geeignet dotiert sein, siehe Sze 1969; Pierret 1996; Sze 1998. In diesem Ausführungsbeispiel ist auf das Aufbringen der ersten Isolierschicht 6 verzichtet worden, die photoempfindliche Schicht 3 liegt also direkt auf dem elektronischen Bauteil 1 auf. Weil das elektronische Bauteil 1 in der Regel aus mehreren Schichten, z. B. Halblei- ter/Metall/Isolator, besteht, kann in dieser Ausführungsform nicht mehr zwischen dem elektronischen Bauteil 1 und den an- deren MSM-Strukturen unterschieden werden, die MSM-Struktur kann als Teil des elektronischen Bauteils 1 gesehen werden. Somit kann das MSM-Element M auch so aufgefasst werden, dass im Substrat ein elektronischer Baustein 1, insbesondere ein in VLSI-Technik gefertigter ASIC, integriert ist. Diese Vorgehensweise ist billiger als die Verwendung verschiedener Halbleiter für das elektronische Bauteil"! und die lichtempfindliche Schicht 3, da ein Prozessschritt wegfällt. Jedoch lässt sich unter Umständen auch nur ein vergleichsweise geringerer Füllfaktor sowie eine nur begrenzte Verwendungsmöglichkeit verschiedener Halbleitermaterialien errei- chen.In FIG. 3, the light-sensitive layer 3 consists of the same semiconductor base material as the electronic component 1, advantageously Si. The Si in the light-sensitive layer 3 can be suitably doped, see Sze 1969; Pierret 1996; Sze 1998. In this exemplary embodiment, the application of the first insulating layer 6 has been dispensed with, ie the photosensitive layer 3 lies directly on the electronic component 1. Because the electronic component 1 usually consists of several layers, e.g. B. semiconductor / metal / insulator, can no longer be distinguished in this embodiment between the electronic component 1 and the other MSM structures, the MSM structure can be seen as part of the electronic component 1. The MSM element M can thus also be understood such that an electronic component 1, in particular an ASIC produced using VLSI technology, is integrated in the substrate. This procedure is cheaper than using different semiconductors for the electronic component " ! And the photosensitive layer 3, since one process step is omitted. However, under certain circumstances it is also possible to achieve only a comparatively lower fill factor and only a limited use of different semiconductor materials.
Die Elektroden 2 liegen entweder unter der lichtempfindlichen Schicht 3, siehe Fig. 3a, oder eingebettet innerhalb der lichtempfindlichen Schicht 3, siehe Fig. 3 c.The electrodes 2 are either under the photosensitive layer 3, see FIG. 3a, or embedded within the photosensitive layer 3, see FIG. 3c.
Vorzugsweise werden die von CMOS-Kameras bekannten Materia- lien und Prozesse angewendet. Die Elektroden 2 werden durch geeignete Strukturierung der Metallschichten innerhalb des ASIC erzeugt. Die Auskoppelung der Mischsignals und die Ein- koppelung der Modulation kann entweder analog zum vorherigen Ausführungsbeispiel durch Verbindung mit tiefer gelegenen Me- tallisierungsschichten erfolgen, oder seitlich durch Zuführungen, die eine Verbindung zu außerhalb der in der gleichen Schicht liegenden Teilen herstellen.The materials and processes known from CMOS cameras are preferably used. The electrodes 2 are produced by suitable structuring of the metal layers within the ASIC. The coupling out of the mixed signal and the coupling in of the modulation can either be carried out analogously to the previous exemplary embodiment by connecting to lower-lying metallization layers, or laterally by means of leads which produce a connection to parts lying outside in the same layer.
Die Auskopplung des Mischsignals kann in den beiden vorgestellten Ausführungsbeispielen entweder innerhalb des elekt- ronischen Bauteils 1 oder mittels extern angebrachter Filterschaltungen erfolgen. Das elektronische Bauteile 1, hier: das ASIC, kann selbst wieder entweder mittels herkömmlicher Wirebonds von der Seite kontaktiert werden oder bei geeigneter Anordnung der Pads unter dem ASIC mittels Flip-Chip-Technik, z. B. Finepitch-Flip-Chip-Technik.In the two exemplary embodiments presented, the coupling signal can be decoupled either within the electronic component 1 or by means of externally attached filter circuits. The electronic component 1, here: the ASIC, can itself either be contacted again from the side by means of conventional wirebonds or, if the pads are arranged appropriately under the ASIC, using flip-chip technology, for. B. Fine pitch flip chip technology.
Figur 4 zeigt eine Sandwich-BIMSM-Struktur M', bei der kein Halbleitersubstrat verwendet wird, sondern die Elektroden 2 direkt auf einen Isoliersubstrat 1', insbesondere einem kera- mischen oder Glas-Substrat, siehe z. B. L.-H. Laih 1999, aufgetragen sind und dann mit einer oder mehreren lichtempfindlichen Halbleiterschichten 3 beschichtet wurden. Dabei können die Elektroden 2 entweder flach ausgeführt werden, oder zur Verbesserung der Feldverteilung in die lichtempfindliche Schicht 3 hineinragen. Bei dieser Ausführungsform erfolgt die Trennung zischen Mischsignal und Modulationssignal mittels eines auf dem Substrat realisierten diskreten Filters 11. Anschließend können die Werte direkt von der externen Peripherie aufgenommen werden, z. B. in einem auf das Substrat 1' aufgebrachten integrierten Schaltkreis IC, hier einer Auslese- und/oder Weiterverarbeitungseinheit 7, gespeichert und/oder weiterverarbeitet werden.FIG. 4 shows a sandwich BIMSM structure M ', in which no semiconductor substrate is used, but rather the electrodes 2 directly on an insulating substrate 1', in particular a ceramic or glass substrate, see, for example, BL-H. Laih 1999, are applied and then coated with one or more photosensitive semiconductor layers 3. The electrodes 2 can either be flat or protrude into the light-sensitive layer 3 to improve the field distribution. In this embodiment, the Separation between mixed signal and modulation signal by means of a discrete filter 11 implemented on the substrate. The values can then be recorded directly from the external periphery, eg. B. in an applied to the substrate 1 'integrated circuit IC, here a readout and / or further processing unit 7, stored and / or processed.
Dieses Verfahren ermöglicht eine kostengünstige Realisierung großflächiger Strukturen. Bei entsprechen strukturierbaren Substraten 1', z.B. LTCC Keramiken und/oder Hochfrequenzkeramiken, können die Ausleseschaltung 7 und weitere Elektronik, gegebenenfalls in Verbindung mit diskreten Bauteilen 11, IC, direkt modular auf dem Substrat 1' realisiert werden, z. B. in Flip-Chip-Technik. Allgemein, also auch in allen drei Ausführungsformen, kann die Kombination aus Elektroden 2 und lichtempfindlicher Schicht 3 so gewählt werden, dass sich entweder ein Schottky- oder ein ohmscher Übergang ausbildet. Des weiteren können auch entsprechend dotierte n-i-n-Übergänge verwendet werden. Zu den genannten Übergängen siehe u.a. Sze 1969; Pierret 1996; Sze 1998.This process enables large-scale structures to be implemented cost-effectively. With correspondingly structurable substrates 1 ', e.g. LTCC ceramics and / or high-frequency ceramics, the read-out circuit 7 and further electronics, optionally in connection with discrete components 11, IC, can be implemented directly modularly on the substrate 1 ', for. B. in flip-chip technology. In general, that is to say also in all three embodiments, the combination of electrodes 2 and light-sensitive layer 3 can be selected such that either a Schottky or an ohmic transition is formed. Correspondingly doped n-i-n junctions can also be used. For the above-mentioned transitions see among others Sze 1969; Pierret 1996; Sze 1998.
Bevorzugt werden für die Schichten 2,3 die in Fischer 1996 genannten Dünnfilm-Kombinationen verwendet, da diese mit Standardprozessen kompatibel ist. Von besonderem Interesse ist zudem die Ausgestaltung der Elektroden 2 bzw. Vias 5 und Zuführungen 5' aus verschiedenen Metallen, um an einer Stelle einen Schottky-Übergang, z.B. beim Kontakt Elektroden 2 - photoempfindliche Schicht 3, an anderer Stelle hingegen einen ohmschen Kontakt zu realisieren, z.B. beim Kontakt Elektroden 2 - Auswerteschaltung 7.The thin film combinations mentioned in Fischer 1996 are preferably used for the layers 2, 3, since this is compatible with standard processes. Of particular interest is also the design of the electrodes 2 or vias 5 and feeds 5 'made of different metals in order to have a Schottky junction, e.g. with contact electrodes 2 - photosensitive layer 3, however, to realize an ohmic contact elsewhere, e.g. contact electrodes 2 - evaluation circuit 7.
Allgemein, also auch in allen drei Ausführungsformen, besteht eine bevorzugte Ausführung darin, die Schichtdicken, z. B. die Dicken a, b, c in Fig. 3, so zu wählen, dass sie einem Bruchteil bzw. einem Vielfachen des Bruchteiles der einfal- lenden Wellenlänge entspricht und der Bruchteil so gewählt wird, das der Übergang Luft-lichtempfindliche Schicht 3 bzw. Passivierungsschicht 4 - lichtempfindliche Schicht 3 oder Luft - lichtempfindliche Schicht 3 wellenlängenselektiv ist. Bevorzugte Bruchteile sind ein Viertel und ungerade Vielfache davon. Dabei kann entweder die z. B. gesamte Schicht c, oder der Teil a über den Elektroden, die Elektrodendicke b-a und der Teil c-b unter den Elektroden entsprechend gewählt werden.In general, that is also in all three embodiments, a preferred embodiment consists in the layer thicknesses, for. B. to choose the thicknesses a, b, c in FIG. 3 so that they correspond to a fraction or a multiple of the fraction of the incident wavelength and the fraction is chosen such that the transition from air-photosensitive layer 3 or , Passivation layer 4 - photosensitive layer 3 or air - photosensitive layer 3 is wavelength selective. Preferred fractions are a quarter and odd multiples thereof. Either the z. B. entire layer c, or part a over the electrodes, the electrode thickness ba and part cb under the electrodes are chosen accordingly.
Weiterhin kann die Empfindlichkeit allgemein dadurch gesteigert werden, dass nach der lichtempfindlichen Schicht 3 ein spiegelnder Übergang auf die nächste Schicht vorliegt, wodurch nicht absorbiertes Licht in die lichtempfindliche Schicht 3 zurückgeworfen wird, wo es dann noch absorbiert. Dies ist auch zur Realisierung einer dünneren Schicht günstig. Die Reflexion am Ende der lichtempfindlichen Schicht kann unter anderem durch einen anderen Brechungsindex der nächsten Halbleiterschicht oder durch Einziehen einer dünnen Metallschicht 9 realisiert werden.Furthermore, the sensitivity can generally be increased in that after the photosensitive layer 3 there is a specular transition to the next layer, as a result of which non-absorbed light is reflected back into the photosensitive layer 3, where it then still absorbs. This is also advantageous for realizing a thinner layer. The reflection at the end of the light-sensitive layer can be realized, inter alia, by a different refractive index of the next semiconductor layer or by drawing in a thin metal layer 9.
Des weiteren kann auf der lichtempfindlichen Schicht 3 eine durchsichtige Passivierungsschicht 4 aufgebracht werden, z. B. um eine Oberflächenoxidation oder einen Abrieb zu verhindern. Diese Passivierungsschicht 4 kann zudem als Antirefle- xionsschicht ausgeführt sein oder in Verbindung mit dem Übergang zwischen der photoempfindlichen Schicht 3 und der darunter liegenden Schicht einen Fabry-Perot- oder Bragg-Resonator bilden, siehe dazu Kowalsky and Prank 1993; Litvin, Burm et al. 1993) und (Bassous, Halbout et al . 1994.Furthermore, a transparent passivation layer 4 can be applied to the light-sensitive layer 3, e.g. B. to prevent surface oxidation or abrasion. This passivation layer 4 can also be designed as an antireflection layer or, in connection with the transition between the photosensitive layer 3 and the layer below it, form a Fabry-Perot or Bragg resonator, see Kowalsky and Prank 1993; Litvin, Burm et al. 1993) and (Bassous, Halbout et al. 1994.
Geeignete Betriebsschaltungen für die Verwendung von FIMSM- Elementen als elektrooptische Mischer sind in (Ruff, Bruno et al . 2000; Shen, Stead et al. 2000) zu finden. Dabei kann man prinzipiell zwischen einseitiger und zweiseitiger Modulation unterscheiden. Bei einer üblichen Schaltung wird die Spannung an einer der beiden Fingerstrukturen mit einer bestimmten Frequenz moduliert. Der andere Finger wird auf eine konstante Biasspannung gelegt, und mittels eines Filters wird das Mischsignal ausgekoppelt. Eine solche Ausleseschaltung wird günstigerweise auch in jedem Pixel Ml,...,Mmn der Sandwich- BIMSM-Struktur integriert. Bevorzugt wird dabei die frequenz¬ abhängige Verstärkung der integrierten Verstärker so gewählt, dass ein vorgeschaltete Filter entfallen kann. Ein besonderer Vorteil dieser Anordnung ist, dass eine Entkoppelung der mo- dulierten Elektroden 2 aller Pixel Ml,...,Mmn entfällt, d.h. diese werden einfach verbunden und direkt zum Kontakt geführt .Suitable operating circuits for the use of FIMSM elements as electro-optical mixers can be found in (Ruff, Bruno et al. 2000; Shen, Stead et al. 2000). In principle, one can differentiate between one-sided and two-sided modulation. In a conventional circuit, the voltage on one of the two finger structures is modulated with a certain frequency. The other finger is placed on a constant bias voltage, and the mixed signal is coupled out by means of a filter. Such a read-out circuit is advantageously also in every pixel Ml, ..., Mmn of the sandwich BIMSM structure integrated. The frequency dependent gain ¬ of the integrated amplifier is preferably selected such that an upstream filter can be omitted. A particular advantage of this arrangement is that there is no need to decouple the modulated electrodes 2 of all pixels Ml,..., Mmn, ie they are simply connected and led directly to the contact.
Fig. 5 zeigt ein BIMSM-Array MAR mit einer Vielzahl von (mxn) MSM-Elementen Ml, M2, Mn+1, Mn+2, ... (Pixeln) , die in zwei Richtungen n/m weitergeführt werden, wie durch die Punkte und Pfeile angedeutet. Sollte dabei die Kapazität aller verbundenen Modulationselektroden zu groß werden, können, z. B. im Substrat 1, Treiber 10 für die Modulationsspannung integriert werden, z. B. in jedem Pixel Ml, M2,...,Mn+l, Mn+2,...,Mnm (durch die Dreiecke angedeutet), oder bei Anordnung im Array MAR zu Beginn jeder Array-Zeile 1 ... n bzw. 1 ... m.FIG. 5 shows a BIMSM array MAR with a plurality of (mxn) MSM elements Ml, M2, Mn + 1, Mn + 2, ... (pixels), which are continued in two directions n / m, as by the dots and arrows indicated. Should the capacity of all connected modulation electrodes become too large, e.g. B. in the substrate 1, driver 10 for the modulation voltage, z. B. in each pixel Ml, M2, ..., Mn + l, Mn + 2, ..., Mnm (indicated by the triangles), or when arranged in the array MAR at the beginning of each array line 1 ... n or 1 ... m.
In manchen Fällen kann ein höherer technischer Aufwand zur Unterdrückung von Störsignalen erforderlich sein. Dann werden beide Elektroden des jeweiligen Elektrodenpaars 2 komplementär moduliert, und an jeder der beiden Elektroden 2 wird das Mischprodukt ausgekoppelt. Das Modulationssignal wird in dieser Ausführungsform über einen gemeinsamen Leiter 14 eingespeist; über seitliche Kontaktierungen 5', sind die Pixel Ml, M2,...,Mn+l, Mn+2,...,Mnm mit die mit einer Pixelelektronik 8 (nicht dargestellt) verbunden, die das Bias liefert, ein Ausgangssignal filtert und verstärkt sowie evtl. das Signal speichert und eine Adressierlogik umfasst.In some cases, a higher technical effort to suppress interference signals may be required. Then both electrodes of the respective pair of electrodes 2 are modulated in a complementary manner, and the mixed product is coupled out at each of the two electrodes 2. In this embodiment, the modulation signal is fed in via a common conductor 14; The pixels Ml, M2, ..., Mn + 1, Mn + 2, ..., Mnm are connected via side contacts 5 'to an electronic signal filter (not shown) which supplies the bias and filters an output signal and amplifies and possibly stores the signal and includes addressing logic.
Anschließend können gemeinsame Störungen mittels Differenzbildung unterdrückt werden, ähnlich dem Stand der Technik für PMD-Sensoren nach (Schwarte 1997; Schwarte 1997) . Bevorzugt wird eine solche Schaltung in jedes Pixel Ml, M2, Mn+1, Mn+2, Mnm integriert. Dabei kann das Problem der Entkoppelung der einzelnen Pixel Ml, M2,...,Mn+l, Mn+2, ... ,Mnm beispielsweise entweder durch kapazitive Einkoppelung der Modulatiόnssignale jedes Pixels Ml, M2, Mn+1, Mn+2, Mnm oder durch Integration eines Verstärkers 12 in jedes Pixel Pixel Ml, M2,...,Mn+l, Mn+2,...,Mnm geschehen. Das Auslesen erfolgt dann hinter dem Verstärker 12, wobei wie zuvor entweder ein Filter 11 oder ein angepasster Ausleseverstärker bzw. eine Ausleseeinheit 7 integriert wird.Common disturbances can then be suppressed by means of difference formation, similar to the state of the art for PMD sensors according to (Schwarte 1997; Schwarte 1997). Such a circuit is preferably integrated into each pixel M1, M2, Mn + 1, Mn + 2, Mnm. The problem of decoupling the individual pixels Ml, M2, ..., Mn + 1, Mn + 2, ..., Mnm can be solved either by capacitive coupling of the modulation signals of each pixel Ml, M2, Mn + 1, Mn + 2, Mnm or by integrating an amplifier 12 into each pixel Pixel Ml, M2, ..., Mn + 1, Mn + 2, ..., Mnm. The readout then takes place behind the amplifier 12, with either a filter 11 or an adapted readout amplifier or a readout unit 7 being integrated as before.
Das Auslesen der entsprechenden Signale kann z. B. nach Böhm, Blecher et al. 1998 entweder als Strom- oder als Spannungs- auslese erfolgen. Dabei werden bevorzugt die Ausleseschaltun- gen 7, Speichermöglichkeiten und Adressierungsverfahren der Pixelelektronik 8 in jedem Pixel Pixel Ml, M2,...,Mn+l, Mn+2, ... ,Mnm implementiert. Von besonderem Interesse sind dabei Verfahren mit hoher Dynamik, z. B. nach Lule, Keller et al. 1999. Im Falle der beidseitigen Modulation werden güns- tigerweise Verfahren und Anordnungen, insbesondere zur Differenzbildung nach Schwarte 1997; Schwarte 1997 in jedes Pixel Ml, M2, Mn+1, Mn+2, Mnm integriert.The reading of the corresponding signals can, for. B. according to Böhm, Blecher et al. 1998 either as current or as voltage selection. The readout circuits 7, storage options and addressing methods of the pixel electronics 8 are preferably implemented in each pixel of pixels Ml, M2, ..., Mn + 1, Mn + 2, ..., Mnm. Of particular interest are processes with high dynamics, e.g. B. according to Lule, Keller et al. 1999. In the case of bilateral modulation, methods and arrangements are favorably used, in particular for difference formation according to Schwarte 1997; Rake integrated in every pixel Ml, M2, Mn + 1, Mn + 2, Mnm in 1997.
Ebenfalls günstig sind MSM-Elemente, in die Sigma-Delta Konverter integriert werden, siehe analog dazu Gulden, Vossiek et al. 2000 für PMDs .MSM elements into which sigma-delta converters are integrated are also inexpensive, see analogously to this Gulden, Vossiek et al. 2000 for PMDs.
Die "Sandwich-MSM"-Mischer können dann mit den für PMD- Strukturen beschriebenen Modulationsverfahren, z.B. IQ, Pseu- do Noise (Schwarte 1997; Schwarte 1997), 2-Frequenz, FSCW, FMCW (Gulden, Vossiek et al. 2000) beschrieben werden. Des weiteren kann nach eine elektrooptische Regelschleife, unter anderem für die Entfernungsmessung, realisiert werden, siehe z. B. Gulden, Vossiek et al . 2000.The "sandwich MSM" mixers can then be operated using the modulation methods described for PMD structures, e.g. IQ, Pseu- do Noise (Schwarte 1997; Schwarte 1997), 2-Frequency, FSCW, FMCW (Gulden, Vossiek et al. 2000). Furthermore, an electro-optical control loop, for example for distance measurement, can be implemented. B. Gulden, Vossiek et al. 2000th
Aufgrund der deutlich erhöhten Systemverbesserungen, insbesondere in Bezug auf Bandbreite, Dynamik und Genauigkeit kön- nen durch "Sandwich-MSM"-Strukturen neue Anwendungen und Messbereiche erschlossen werden.Due to the significantly increased system improvements, particularly with regard to bandwidth, dynamics and accuracy, "sandwich MSM" structures can open up new applications and measuring ranges.
Figur 6 zeigt ein System zur Entfernungsmessung unter Verwendung eines monolithischen MSM-Arrays MAR. Das System weist eine Lichtquelle Q zur Abstrahlung modulierten Lichtes auf, z. B. eine Laserdiode oder eine LED, dem eine Ausgangsoptik TO nachgeschaltet ist. Das System umfasst weiterhin eine Empfängeroptik RO zur Bündelung des einfallenden modulierten Lichts ST3, welches dann auf das MSM-Array MAR fällt. Die Bündelung des einfallenden Lichts kann durch die Verwendung von bereits für CMOS-Sensoren oder PMD-Systemen verwendeten Optiken und Linsen erfolgen, siehe Tai, Schwarte et al . 2000.FIG. 6 shows a system for distance measurement using a monolithic MSM array MAR. The system has a light source Q for emitting modulated light, e.g. B. a laser diode or an LED, the output optics TO is connected downstream. The system further comprises a receiver optics RO for bundling the incident modulated light ST3, which then falls on the MSM array MAR. The incident light can be bundled by using optics and lenses already used for CMOS sensors or PMD systems, see Tai, Schwarte et al. 2000th
Das MSM-Array MAR kann mittels einer Auslese- und/oder Weiterverarbeitungseinheit 7, beispielsweise eines Computers, eines Digitalen Signalprozessors, eines Mikroprozessors oder eines FPGA, gesteuert werden. Die Auslese- und/oder Weiterverarbeitungseinheit 7 empfängt Daten SIG3 vom MSM-Array MAR und liefert diesem ein Ansteuersignal SIG2. Sie gibt in diesem Ausführungsbeispiel auch Messdaten OUT aus, z. B. Daten zur Entfernungsmessung, liefert ein Ansteuersignal SIG1 für die Pixelelektronik 8 (hier: Modulationselektronik), welche wiederum das MSM-Array MAR und die Lichtquelle Q steuert.The MSM array MAR can be controlled by means of a readout and / or further processing unit 7, for example a computer, a digital signal processor, a microprocessor or an FPGA. The readout and / or further processing unit 7 receives data SIG3 from the MSM array MAR and supplies it with a control signal SIG2. In this exemplary embodiment, it also outputs measurement data OUT, e.g. B. data for distance measurement, provides a control signal SIG1 for the pixel electronics 8 (here: modulation electronics), which in turn controls the MSM array MAR and the light source Q.
Ein solches System kann z.B. zur Überwachung der Sitzposition im Auto angewendet werden (Mengel and Doemens 1997; Doemens and Mengel 1998) . Ein ähnliches System kann auch zur Überwa- chung des Autoaußenraums eingesetzt werden (Schwarte, Buxbaum et al. 2000). Bevorzugte Realisierungen dieser Systeme benutzen Infrarotlicht, um den Autofahrer nicht zu stören. Von besonderem Interesse ist dabei die Beachtung der Normen für Augensicherheit (VDE 1994), was durch die Verwendung von Licht mit einer Wellenlänge größer 1400 nm, sowie geeigneter Empfangsmaterialien erleichtert wird. Die geeignete Materialien gemäß dem Stand der Technik sind u.a. in (Sze 1969; Pierret 1996; Sze 1998) wiedergegeben. Bevorzugte Montagepositionen sind direkt hinter der Windschutzscheibe, oder in den vorhan- denen Scheinwerfern.Such a system can e.g. to monitor the seating position in the car (Mengel and Doemens 1997; Doemens and Mengel 1998). A similar system can also be used to monitor the exterior of the car (Schwarte, Buxbaum et al. 2000). Preferred implementations of these systems use infrared light so as not to disturb the driver. Of particular interest is the observance of the standards for eye safety (VDE 1994), which is facilitated by the use of light with a wavelength greater than 1400 nm and suitable receiving materials. Suitable materials according to the state of the art include in (Sze 1969; Pierret 1996; Sze 1998). Preferred mounting positions are directly behind the windshield or in the existing headlights.
Vergleichbare Systeme mit direkter Stromauslese können erfindungsgemäß als Phasendetektoren in elektrooptischen Regelschleifen, z.B. in einer PLL , als Phasendetektor zur Taktsynchronisation oder als Demodulator in z.B. in CDMA oder QPSK Kommunikationssystemen eingesetzt werden (Buxbaum, Schwarte et al . 2000). Baker, J.R., Li, H.W. et al. (1998). CMOS. Circuit Design, Layout, and Simulation; IEEE 1998 Bassous, E., J.-M. Halbout, et al . (1994). High Speed Sili- con-Based Lateral Junction Photodetectors Having Reces- sed Electrodes and Thick Oxide to Reduce Fringing Fields. 5,525,828. United States, International Business Machines Corporation: 28. Böhm, M., F. Blecher, et al . (1998). High Dynamic Range Image Sensors in Thin Film on ASIC Technology for Automotive Applications. Advanced Microsystems for Automotive Applications 98, Springer. Buxbaum, B., R. Schwarte, et al . (2000). Optisches CDMA auf Basis der PMD-Technologie. Fachtagung "Optik in der Rechentechnik 2000", Hagen. Doemens, G. and P. Mengel (1998) . Verfahren und Vorrichtung zur Aufnahme eines dreidimensionalen Entfernungsbildes. DE 198 33 207 A 1. Germany, Siemens AG: 14. Fischer, H. (1996) . Ein analoger Bildsensor in TFA (Thin Film on ASIC) -Technology. Elektrotechnik. Siegen, Universität GH Siegen: 133. Gulden, P. G., M. Vossiek, et al . (2000). PMD Element. Mu- nich, Siemens ZT MS 1: 18. Gulden, P. G., M. Vossiek, et al . (2000). PMD System. Germany, Siemens AG: 34. Gulden, P. G., M. Vossiek, et al . (2000). Verfahren und Vorrichtungen zum Betrieb eines PMD-System. Germany: 42. Kim, J. H., H. T. Griem, et al . (1992). NHigh-performance back-illuminated InGaAs/InAlAs MSM photodetector with a record responsivity of 0.96 A/W." IEEE PHOTONICS TECHNOLOGY LETTERS 4(11): 1241-1244. Kowalsky, W. and U. Prank (1993) . Planar MSM-modulators and photodetectors with integrated Fabry-Perot resonator for arrayed configurations in high bandwidth optical inter- connects. SPIE Optoelectronic Interconnects, SPIE. L.-H. Laih, T.-C. C, Y.-A. Chen, W.-C. Tsay, T.-S. Jen, J.- W. Hong (1999) . 'Amorphous metal-semiconductor-metal photodetector (MSM-PD) with botto ridged Cr electro- des." Electronics Letters 35(12): 1021-1022. Litvin, K., J. Burm, et al. (1993). High Speed Optical Detec- tors for Monolithic Milimeter Wave Integrated Circuits. IEEE MTT-S International Microwave Symposium Digest, Atlanta, IEEE. Liu, Q. Z. and R. I. MacDonald (1993). ^Controlled nonlinea- rity monolithic integrated optoelectronic mixing recei- ver." IEEE PHOTONICS TECHNOLOGY LETTERS 5(12): 1403- ' 1406. Lule, T., H. Keller, et al . (1999). 100.000 Pixel 120dBComparable systems with direct current reading can be used according to the invention as phase detectors in electro-optical control loops, for example in a PLL, as phase detectors for clock synchronization or as demodulators in, for example, CDMA or QPSK communication systems (Buxbaum, Schwarte et al. 2000). Baker, JR, Li, HW et al. (1998). CMOS. Circuit design, layout, and simulation; IEEE 1998 Bassous, E., J.-M. Halbout, et al. (1994). High Speed Silicon-Based Lateral Junction Photodetectors Having Recessed Electrodes and Thick Oxide to Reduce Fringing Fields. 5,525,828. United States, International Business Machines Corporation: 28. Boehm, M., F. Blecher, et al. (1998). High Dynamic Range Image Sensors in Thin Film on ASIC Technology for Automotive Applications. Advanced Microsystems for Automotive Applications 98, Springer. Buxbaum, B., R. Schwarte, et al. (2000). Optical CDMA based on PMD technology. Conference "Optics in Computing 2000", Hagen. Doemens, G. and P. Mengel (1998). Method and device for recording a three-dimensional distance image. DE 198 33 207 A 1. Germany, Siemens AG: 14. Fischer, H. (1996). An analog image sensor in TFA (Thin Film on ASIC) technology. Electrical engineering. Siegen, University of Siegen: 133. Gulden, PG, M. Vossiek, et al. (2000). PMD element. Munich, Siemens ZT MS 1: 18. Gulden, PG, M. Vossiek, et al. (2000). PMD system. Germany, Siemens AG: 34th Gulden, PG, M. Vossiek, et al. (2000). Methods and devices for operating a PMD system. Germany: 42. Kim, JH, HT Griem, et al. (1992). N High-performance back-illuminated InGaAs / InAlAs MSM photodetector with a record responsivity of 0.96 A / W. "IEEE PHOTONICS TECHNOLOGY LETTERS 4 (11): 1241-1244. Kowalsky, W. and U. Prank (1993). Planar MSM -modulators and photodetectors with integrated Fabry-Perot resonator for arrayed configurations in high bandwidth optical inter- connects.SPIE Optoelectronic Interconnects, SPIE. L.-H. Laih, T.-C. C, Y.-A. Chen, W.-C. Tsay, T.-S. Jen, J.-W. Hong (1999). 'Amorphous metal-semiconductor-metal photodetector (MSM-PD) with botto ridged Cr electrodes. "Electronics Letters 35 (12): 1021-1022. Litvin, K., J. Burm, et al. (1993). High Speed Optical Detectors for Monolithic Milimeter Wave Integrated Circuits. IEEE MTT-S International Microwave Symposium Digest, Atlanta, IEEE. Liu, QZ and RI MacDonald (1993). ^ Controlled nonlinearity monolithic integrated optoelectronic mixing receiver. " IEEE PHOTONICS TECHNOLOGY LETTERS 5 (12): 1403- '1406. Lule, T., H. Keller, et al. (1999). 100,000 pixels 120dB
Imager for Automotive Vision. Advanced Microsystesm for Automotive Applications 99, Berlin, Springer.Imager for Automotive Vision. Advanced Microsystm for Automotive Applications 99, Berlin, Springer.
MacDonald, R. I. and B. E. Swekla (1990). *Frequency domain optical reflectometer using a GaAs optoelectronic mi- xer." Applied Optics 29(31): 4578-4582. Mengel, P. and G. Doemens (1997) . Verfahren und Vorrichtung zur Aufnahme eines mehrdimensionalen Entfernungsbildes. DE 197 57 595 A 1. Germany, Siemens AG: 9. Pierret, R. F. (1996). Semiconductor Device Fundamentals.MacDonald, R.I. and B.E. Swekla (1990). * Frequency domain optical reflectometer using a GaAs optoelectronic mixer. "Applied Optics 29 (31): 4578-4582. Mengel, P. and G. Doemens (1997). Method and device for recording a multidimensional distance image. DE 197 57 595 A 1. Germany, Siemens AG: 9. Pierret, RF (1996) Semiconductor Device Fundamentals.
Reading, Massachusetts, Addison-Wessley Publishing Company. Ruff, W., J. Bruno, et al . (2000). Self-mixing detector can- didates for an FM/cw ladar architecture. SPIE Laser Radar Technology and Applications V, SPIE. Schwarte, R. (1997) . Verfahren und Vorrichtung zur Bestimmung der Phasen- und /oder Amplitudeninformation einer elekt- romagnetischen Welle. DE 197 04 496 A 1. Germany, R. Schwarte: 26. Schwarte, R. (1997) . Vorrichtung und Verfahren zur Erfassung von Phasen- und Amplitudenelektromagnetischen Wellen. DE 197 04 496 A 1. Germany, R. Schwarte: 20. Schwarte, R., B. Buxbaum, et al . (2000). New powerful sensory tool in Automotive Safety Systems Based on PMD- Technology. Advances in Automotive imaging, Springer Verlag? Shen, P. H., M. Stead, et al. (2000). Interdigitated finger semiconductor photodetector . SPIE Aerosense, 24-28 April 2000, SPIE.Reading, Massachusetts, Addison-Wessley Publishing Company. Ruff, W., J. Bruno, et al. (2000). Self-mixing detector can- didates for an FM / cw ladar architecture. SPIE Laser Radar Technology and Applications V, SPIE. Schwarte, R. (1997). Method and device for determining the phase and / or amplitude information of an electromagnetic wave. DE 197 04 496 A 1. Germany, R. Schwarte: 26. Schwarte, R. (1997). Device and method for detecting phase and amplitude electromagnetic waves. DE 197 04 496 A 1. Germany, R. Schwarte: 20. Schwarte, R., B. Buxbaum, et al. (2000). New powerful sensory tool in Automotive Safety Systems Based on PMD Technology. Advances in automotive imaging, Springer Verlag? Shen, PH, M. Stead, et al. (2000). Interdigitated finger semiconductor photodetector. SPIE Aerosense, April 24-28, 2000, SPIE.
Sze, S. M. (1969). Physics of Semiconductor Devices. New Y- ork, John Wiley & Sons. Sze, S. M. (1998). Modern Semiconductor Devices. New York, Wiley. Tai, W., Schwarte, R. et al (2000). Optimisation of the light transmission and irradiance distribution of an aspheri- cal lens for 3-D time-of-flight Sensors VDE (1994) . Sicherheit von Laser-Einrichtungen, Teil 1 DIN EN 60825-1, VDE 0837, Teil 1, VDE/DIN: 77. Sze, S. M. (1969). Physics of Semiconductor Devices. New Y-ork, John Wiley & Sons. Sze, S. M. (1998). Modern semiconductor devices. New York, Wiley. Tai, W., Schwarte, R. et al (2000). Optimization of the light transmission and irradiance distribution of an aspherical lens for 3-D time-of-flight sensors VDE (1994). Safety of laser devices, part 1 DIN EN 60825-1, VDE 0837, part 1, VDE / DIN: 77.

Claims

Patentansprüche claims
1. Rückseitenbeleuchtbares MSM-Element (M,M'), mindestens aufweisend - ein Substrat (1,1'), ein oberhalb des Substrats (1,1') angebrachtes Elektrodenpaar (2) ,1. Back-lightable MSM element (M, M '), at least comprising - a substrate (1,1'), an electrode pair (2) attached above the substrate (1,1 '),
- mindestens eine mindestens auf dem Elektrodenpaar (2) angebrachte lichtempfindliche Schicht (3) , welche auf der dem Elektrodenpaar (2) abgewandten Seite bestrahlbar ist, dadurch gekennzeichnet, dass zumindest das Substrat (1,1'), das Elektrodenpaar (2) und die lichtempfindliche Schicht (3) gemeinsam monolit- hisch aufgebaut sind,- At least one at least on the pair of electrodes (2) attached photosensitive layer (3) which can be irradiated on the side facing away from the pair of electrodes (2), characterized in that at least the substrate (1, 1 '), the pair of electrodes (2) and the light-sensitive layer (3) is constructed monolithically together,
- mindestens eine Elektrode des Elektrodenpaars (2) zur Einkopplung einer Modulationsspannung verwendbar ist,at least one electrode of the pair of electrodes (2) can be used to couple in a modulation voltage,
- mindestens eine Elektrode des Elektrodenpaars (2) zur Auskopplung eines Mischproduktes verwendbar ist, - das MSM-Element (M,M' ) als elektrooptischer Mischer einsetzbar ist.- At least one electrode of the pair of electrodes (2) can be used to couple out a mixed product, - The MSM element (M, M ') can be used as an electro-optical mixer.
2. MSM-Element (M,M') nach Anspruch 1, bei dem die lichtempfindliche Schicht (3) mit einer Passivierungs- Schicht (4) beschichtet ist.2. MSM element (M, M ') according to claim 1, in which the light-sensitive layer (3) is coated with a passivation layer (4).
3. MSM-Element (M,M') nach einem der Ansprüche 1 oder 2, bei dem zwischen Substrat (1,1') und Elektrodenpaar (2) eine erste Isolierschicht (6) vorhanden ist.3. MSM element (M, M ') according to one of claims 1 or 2, in which a first insulating layer (6) is present between the substrate (1, 1') and the pair of electrodes (2).
4. MSM-Element (M) nach einem der Ansprüche 1 bis 3, bei dem im Substrat (1) ein elektronischer Baustein, insbesondere ein in VLSI-Technik gefertigter ASIC, integriert ist.4. MSM element (M) according to one of claims 1 to 3, in which an electronic component, in particular an ASIC manufactured in VLSI technology, is integrated in the substrate (1).
5. MSM-Element (M) nach Anspruch 4, bei dem die lichtempfindliche Schicht (3) kristallin im elektronischen Baustein (1) integriert ist. 5. MSM element (M) according to claim 4, in which the light-sensitive layer (3) is integrated crystalline in the electronic module (1).
6. MSM-Element (M1) nach einem der Ansprüche 1 bis 3, bei dem das Substrat ein isolierendes Substrat (!') ist, insbesondere aus Keramik oder Glas ist.6. MSM element (M 1 ) according to any one of claims 1 to 3, wherein the substrate is an insulating substrate (! '), In particular made of ceramic or glass.
7. MSM-Element (M) nach einem der vorhergehenden Ansprüche, bei dem die lichtempfindliche Schicht (3) als amorpher Dünnfilm aufgebracht ist, insbesondere mit Silizium als Grundmaterial .7. MSM element (M) according to one of the preceding claims, in which the light-sensitive layer (3) is applied as an amorphous thin film, in particular with silicon as the base material.
8. MSM-Element (M,M') nach einem der vorhergehenden Ansprüche, dessen Schichtdicken (a,b,c) so gewählt sind, dass die Durchlässigkeit der Grenzfläche zur lichtempfindlichen Schicht (3) wellenlängenselektiv ist, insbesondere falls die Schichtdicken (a,b,c) einem Viertel oder einem Vielfa- chen der bevorzugten Wellenlänge entsprechen.8. MSM element (M, M ') according to any one of the preceding claims, the layer thicknesses (a, b, c) are selected so that the permeability of the interface to the photosensitive layer (3) is wavelength-selective, especially if the layer thicknesses (a , b, c) correspond to a quarter or a multiple of the preferred wavelength.
9. MSM-Array (MAR), aufweisend mindestens zwei MSM-Elerαente (M,M') mit jeweils integrierten Auswerteschaltungen (7), insbesondere angeschlossen an eine gemeinsame Pixelelektronik (8) .9. MSM array (MAR), having at least two MSM elements (M, M '), each with integrated evaluation circuits (7), in particular connected to a common pixel electronics (8).
10. MSM-Array (MAR) nach Anspruch 9, bei dem in jedem MSM-Element (M,M') einzeln eine Ausleseschaltung (7) integriert ist.10. MSM array (MAR) according to claim 9, in which a read-out circuit (7) is individually integrated in each MSM element (M, M ').
11. MSM-Array (MAR) nach Anspruch 9 oder 10, bei dem die frequenzabhängige Verstärkung so gewählt ist, dass auf einen vorgeschalteten Filter verzichtet werden kann.11. MSM array (MAR) according to claim 9 or 10, in which the frequency-dependent gain is selected such that an upstream filter can be dispensed with.
12. Verfahren zur Herstellung eines MSM-Elements (M,M'), bei dem12. A method for producing an MSM element (M, M '), in which
- das Substrat (1,1') mindestens mit der Leiterstruktur (2) beschichtet wird,- The substrate (1,1 ') is coated at least with the conductor structure (2),
- mindestens die Leiterstruktur (2) derart beschichtet wird, das sich darauf die Halbleiterstruktur (2) bildet. - At least the conductor structure (2) is coated such that the semiconductor structure (2) forms thereon.
EP02747215A 2001-07-05 2002-06-12 Back-illuminated msm module Withdrawn EP1405351A2 (en)

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PCT/DE2002/002151 WO2003005454A2 (en) 2001-07-05 2002-06-12 Back-illuminated msm module

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