Active solid-state devices (e.g. – transistors – solid-state diode – Responsive to non-electrical signal – Electromagnetic or particle radiation
Reexamination Certificate
2000-02-25
2001-10-30
Meier, Stephen D. (Department: 2822)
Active solid-state devices (e.g., transistors, solid-state diode
Responsive to non-electrical signal
Electromagnetic or particle radiation
C257S225000
Reexamination Certificate
active
06310382
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a multicolor sensor and to optoelectronic components.
BACKGROUND OF THE INVENTION
Two-terminal components are known as state of the art. These optoelectronic components contain two contacts (terminals) with a p-n-semiconductor structure lying therebetween to produce a photo current upon light incidence. It is a drawback that the voltage must be switched so that a red-green-blue (RGB) signal can be enabled sequentially from a time point of view.
An nipin-layer structure with a photosensitive electrical component between two outer contacts and based upon amorphous silicon is already known from U.S. Pat. No. 5,311,047. A piiin structure has also been proposed as a photosensitive electrical component with two outer contacts on the basis of amorphous silicon.
In addition, three-terminal components are known as state of the art. A first proposal for constructing pin/TCO [transparent conductive oxide]
ipin structure as a three-terminal component has already been published in M. Topic, F. Smole, J. Furlan, W. Kusian, J. of Non-Cryst. Solids 198-299 (1996) 1180-1184. Here as well the drawback of sequential switching of the voltage applies.
Finally, so-called charge-coupled devices (CCD) are known in which, however, the drawback of the color Moirée-effect complicates the digital signal acquisition.
In the described structures for forming such two-terminal or three-terminal components, the absorber layer of the individual diodes can be adjusted as a function of the color separation anticipated.
The hitherto known vertically integrated color detectors are based upon the requirement that the voltage applied across the detector is altered to obtain the complete color information. For this purpose at least three and usually more switching voltages are required.
OBJECT OF THE INVENTION
It is, therefore, the object of the invention to provide a multicolor sensor in thin-film technology whereby a sequential alteration of the voltage applied to the detector is not required to obtain the complete color information.
SUMMARY OF THE INVENTION
The objects are achieved, according to the invention in that a component is formed from a multiplicity of diode functions, preferably three, formed from layers, for example, pin-diode functions, nip-diode functions, npin-diode functions and/or pnip diode functions, which are arranged perpendicular to the light incidence direction and are connected with one another.
More particularly, the component according to the invention is based on amorphous silicon and its alloys, microcrystalline silicon and its alloys as well as two transparent conductive contact layers. The layer sequence according to the invention and the components according to the invention enable a simultaneous (parallel) readout of the photo current of the vertically-integrated diodes so that at one and the same place in an array arrangement characterized as a pixel a multiplicity of color signals can be detected simultaneously, for example, a complete red-blue-green (RGB) signal. The spectral sensitivity of this component can be adjusted from the near ultraviolet to the near infrared range by a suitable design of the individual diode functions by adjusting certain parameters like, for example, the respective layer thicknesses.
The invention is directed to the development of a component that permits a vertical color detection by a three-dimensional integration whereby the complete color information per pixel is readable in parallel. Since each upstream diode function in the light-incidence direction acts as an absorber for the diode functions lying therebelow, in an advantageous manner this renders the need for further optical filters superfluous.
For the realization of, for example, a four-terminal component according to the invention, the optical absorption of the individual diode must increase as increasing penetration depth and wavelength of the photons of the irradiating light. The detection concept is based on the fact that in the first diode, the shortest wave light, (e.g. blue light) and in the lowest diode, the longest wave light is absorbed; this applies independently of the selected layer structures of the individual diodes (e.g. whether the diode is of the nip, nipin, npin, pinip, pnip or pin type).
In considering npin- diode structures or pnip-diode structures, on both sides of a transparent contact layer is a respective doped semiconductor layer, especially a p-doped or n-doped layer. Thus via the conductive contact layer, which is preferably constituted as a TCO layer or from microcrystalline p-conducting or n-conducting material, only one charge-carrier type can be injected or collected since at the following p
-heterotransition or n/p heterotransition, there is a charge-carrier reversal.
Because of the transition from a two-terminal to a four-terminal component, all three RGB signals are read out simultaneously rather than sequentially. The multiple sensor of the invention and the component according to the invention have the advantage that by vertical integration of the components with simultaneous detection of the signals to be picked up (for detection of, for example, the colors blue, green and red), the color Moireé effect is avoided (as is customary in use of a CCD camera by the provision of special color filters). In addition, in an advantageous manner with the aid of a so-called one-shot pickup, a complete signal can be obtained in the sense of color detection for digital image processing.
REFERENCES:
patent: 4820915 (1989-04-01), Hamakawa et al.
patent: 4875944 (1989-10-01), Yoshida
patent: 5298771 (1994-03-01), Mantell
patent: 5311047 (1994-05-01), Chang
patent: 5352920 (1994-10-01), Morishita et al.
patent: 5738731 (1998-04-01), Shindo et al.
patent: WO 96/13865 (1996-05-01), None
“Stacked a-SiC:H/a-Si:H heterostructures . . .”, by Topic et al., Journal of Non-Crystalline Solids 198-200 (1996).
“Variable spectral response photodetector . . .” by De Cesare et al., Journal of Non-Crystalline Solids 198-200 (1996).
F{overscore (o)}lsch Joachim
Knipp Dietmar
Stiebig Helmut
Wagner Heribert
Dubno Herbert
Forschungszentrum Julich GmbH
Meier Stephen D.
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