Optical sensor element and sensor array
The invention relates to an optical sensor element ( 10 ) which comprises, in a semiconductor substrate ( 1 ), a light-sensitive region ( 18 ) in which charge carriers can be released by irradiation, and two doped regions ( 15, 16 ) for receiving the charge carriers released in the light-sensitive region ( 18 ). The invention is characterized in that electrodes ( 13, 14 ) for generating a field gradient in the light-sensitive region ( 18 ) are insulated from the light-sensitive region ( 18 ) and are disposed in trenches formed in the surface of the substrate ( 1 ).
1 . An optical sensor element ( 10 ) comprising a semiconductor substrate ( 1 ) comprising:
a light sensitive area ( 18 ) in which charge carriers are releasable upon illumination, and
two doping zones ( 15 , 16 ) for receiving charge carriers released from the light sensitive area ( 18 ),
an electrode ( 13 , 14 ) insulated against the light sensitive area ( 18 ) for production of a field gradient in the light sensitive area ( 18 ),
wherein the insulated electrodes ( 13 , 14 ) are provided in grooves formed in the surface of the substrate ( 1 ).
2 . An optical sensor element according to claim 1 , wherein each doping zone ( 15 , 16 ) contacts an insulation layer ( 12 ) of one of the insulated electrodes ( 13 , 14 ).
3 . An optical sensor element according to claim 1 , wherein at each doping zone ( 15 , 16 ) an ohmic contact is formed.
4 . An optical sensor element according to claim 1 , wherein the depth of the grooves is greater than the thickness of the doping zones ( 15 , 16 ).
5 . An optical sensor element according to claim 1 , wherein the depth of the grooves is between 5 and 40 μm deep.
6 . An optical sensor element according to claim 1 , wherein each doping zone ( 15 , 16 ) is associated with a collection condenser for collection of charge carriers extracted from the doping zone ( 15 , 16 ).
7 . An optical sensor element according to claim 6 , wherein each collector condenser includes two conductive plates, which are provided in the grooves of the substrate.
8 . An optical sensor element according to claim 1 , wherein in place of insulated electrodes ( 13 , 14 ) of metal semiconductors structures ( 31 ), built up electrodes are present, which form Schottky barriers ( 30 ) adjacent to to the light sensitive area ( 18 ).
9 . An optical sensor element according to claim 8 , wherein the sensor element does not include any doping zones ( 15 , 16 ).
10 . An optical sensor element according to claim 1 , wherein on the surface of the light sensitive area ( 18 ) an ohmic p + -contact ( 32 ) is diffused in.
11 . An optical sensor array with a plurality of sensors according to claim 1 , wherein respectively two sensor elements ( 10 ) adjacent in a first direction are provided on two sides of a common insulated electrode ( 13 ′).
12 . An optical sensor array according to claim 11 , wherein the common insulated electrode ( 13 ′) bordering doping zones ( 15 , 16 ) of the two sensor elements ( 10 ) are connected electrically conductively.
13 . An optical sensor array according to claim 12 , wherein the two sensor elements ( 10 ) are joined or combined into a pixel.
14 . An optical sensor array according to claim 11 , wherein the doping zones ( 15 , 16 ) bordering the common insulated electrode ( 13 ′) of the two sensor elements ( 10 , 10 ′) are insulated electrically from each other.
15 . An optical sensor array according to claim 14 , wherein the insulating layer ( 12 ) of one of the insulated electrodes ( 13 , 14 ) is thicker at the floor ( 26 ) of its groove than at its side walls ( 27 ).
16 . An optical sensor array with a plurality of sensors according to claim 1 , wherein in between two adjacent insulated electrodes ( 13 , 14 ) of two in a first direction adjacent sensor elements ( 10 ), a zone ( 28 ) is formed insulating the electrodes ( 13 , 14 ).
17 . An optical sensor array according to claim 16 , wherein the insulating zone ( 28 ) is formed by the semiconductor substrate ( 1 ) or a groove.
18 . An optical sensor element according to claim 5 , wherein the depth of the grooves is between 2 and 25 μm deep.