Active solid-state devices (e.g. – transistors – solid-state diode – Responsive to non-electrical signal – Electromagnetic or particle radiation
Reexamination Certificate
2000-02-22
2001-08-28
Ngô, Ngân V. (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
Responsive to non-electrical signal
Electromagnetic or particle radiation
C257S184000, C257S458000, C257S459000, C257S460000
Reexamination Certificate
active
06281561
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a multicolor sensor and to an optoelectronic component having a multicolor sensor.
BACKGROUND OF THE INVENTION
Two-terminal components are known as state of the art. These optoelectronic components contain two contacts (terminals) between which is a p-n semiconductor structure for producing a photon current upon light impingement.
A drawback of this system is that the voltage must be switched so that red-green-blue (RGB) signals are only obtained in a sequentially timed relationship.
On the one hand, in this context, an nipin layer structure is already known from U.S. Pat. No. 5,311,047 as a photosensitive electrical component based upon amorphous silicon with two outer contacts. On the other hand DE 19613820.5-33 proposes a pin structure as a photosensitive electrical component with two outer contacts based upon amorphous silicon.
In addition as state of the art three terminal components are known. A first proposal for producing a pin/TCO
ipin structure as a three-terminal component is already published in M. Topic, F. Smole, J. Furlan, W. Kusian, J. of Non-Cryst. Solids 198-299 (1996) 1180-1184.
Here as well a disadvantage is that the voltage must be sequentially switched.
Finally, so-called charge-coupled devices (CCD) are known in which the color-Moire effect complicates digital signal acquisition.
With the mentioned structures for the formation of such two-terminal components or three-terminal components, the absorber layers of the individual diodes can be adjusted correspondingly as a function of the desired color separation. Known, vertically integrated color detectors are based upon the requirement that the voltage applied to the detector must be sequentially changed to obtain complete color information. For this purpose at least three or in most cases more switched voltages are required.
OBJECT OF THE INVENTION
It is therefore the object of the invention to provide a multicolor sensor in thin layer technology whereby a sequential alteration of the voltage applied to the detector is not required to obtain complete color information.
SUMMARY OF THE INVENTION
The object is achieved with a multicolor sensor with a multiplicity of layer sequences containing diode functions and with p-doped and n-doped layers.
The multicolor sensor has a layer sequence containing a multiplicity of diode functions whereby these diode functions are separated from one another by respective conductive contact layers whereby in consideration of an additional n/p heterotransition or p
heterotransition only one charge carrier type is collected or injected via the inwardly lying contact (whereby for collection or injection only a single charge carrier type via the inwardly lying contact, an additional n/p or p
heterotransition is provided).
A pin
ip, npin and/or pnip structure can form the diode functions.
An additional nonmicrocrystalline or amorphous layer, especially a ZnO layer, can be provided.
The sensor can have four contact layers for producing a RGB sensitivity.
For the case in which the inwardly lying p-layer and n-layer are neighboring without an intervening i-layer or i-layers lying between them, only a respective one of the two p-layer and n-layer is formed as microcrystalline.
The objects are so achieved according to the invention that a component is formed from a multiplicity, preferably three pieces, of layer shaped diode functions, for example, a pin diode function, nip diode function, npin diode function and/or pnip diode function which are arranged perpendicular to the light incidence direction and are connected together. More particularly the component of the invention is above all based upon amorphous silicon and its alloys, microcrystalline silicon and its alloys and, among others, transparent conductive contact layers. The layer sequences according to the invention and the component of the invention enable a simultaneous (parallel) reading of the photocurrent of the vertically integrated diodes so that at one and the same place (designated as a pixel in an array arrangement) a plurality of color signals, for example, a complete red-blue-green (RGB) signal can be detected. The spectral sensitivity of this component can be adjusted by an appropriate design of the individual diode functions by selection of certain parameters like, for example, the respective layer thicknesses, from the near ultraviolet to the near infrared range.
The invention is based upon the fact that a component can be developed which enables a vertical color detection by a three-dimensional integration whereby the complete color information of each pixel can be read in parallel. Since the diode functions which are upstream in the light incidence direction form absorbers for the diode functions lying thereunder, it is advantageous that the need for further optical filters is superfluous.
To produce, for example, a four-terminal component according to the invention, the optical absorption of the individual diodes must increase with increasing penetration depth and the wavelength of the photons of the irradiating light. The detection concept is based on the fact that in the first diode, the shortest wavelength light (for example blue light) is absorbed and in the last diode, the longest wavelength light is absorbed; this applies independently of the selected layer structure of the individual diodes (e.g. nip, nipin, npin, pinip, pnip, or pin).
In a consideration of npin diode structures or pnip diode structures, on both sides of a transparent contact layer respective doped semiconductor layers, especially p-doped or n-doped layers can be provided. Thus via the conductive contact layer, which can preferably be formed as a TCO (transparent conductive oxide) layer or as microcrystalline p-conducting or n-conducting material, only one charge carrier type can be injected or collected, since on the following p
heterotransition or n/p heterotransition, charge carrier exchange occurs.
In the transition from a two-terminal to a four terminal component, all three RGB signals can be simultaneously read out rather than sequentially.
The multicolor sensor according to the invention and the component according to the invention has the advantage that with a vertical integration of the component and simultaneous detection of the signals to be acquired (for detection of the colors blue, green red), the color-Moire effect is avoided (as is customary in CCD camera applications by the use of spatially arranged color filters). Advantageously with the aid of a so-called one shot pickup a complete signal from the point of view of color detection is obtained which can be used for digital image processing.
REFERENCES:
patent: 4875944 (1989-10-01), Yoshida
patent: 5015838 (1991-05-01), Yamagishi et al.
patent: 5923049 (1999-07-01), Bohm et al.
patent: 6043549 (2000-03-01), Gutierrez-Aitken
patent: 6191465 (2001-02-01), Freeouf
Folsch Joachim
Knipp Dietmar
Stiebig Helmut
Wagner Heribert
Dubno Herbert
Forschungszentrum Julich GmbH
Ngo Ngan V.
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