Patent ID: 6452187
Filing Date: 2002-09-17
Classification: H01L

Abstract:
A two-color infrared radiation photodetector comprising:a plurality of first elongate infrared radiation absorbing elements for absorbing a first band of infrared radiation, each of the plurality of first elements having first and second opposite longitudinal surfaces, the plurality of first elements comprising a first diffraction grating for the first band of infrared radiation, the first diffraction grating having a first period; a plurality of second elongate infrared radiation absorbing elements for absorbing a second band of infrared radiation, each of the plurality of second elements having first and second opposite longitudinal surfaces, the plurality of second elements comprising a second diffraction grating for the second band of infrared radiation, the second diffraction grating having a second period; a first electrical contact which includes a plurality of electrically interconnected strips respectively being in electrical contact with and extending along the first surfaces of the plurality of first elements; a second electrical contact being disposed between the plurality of first elements and the plurality of second elements, the second electrical contact having first and second opposite longitudinal surfaces, the second electrical contact including a plurality of electrically interconnected strips, the first surfaces of the second electrical contact being in electrical contact with and extending along the second surfaces of the plurality of first elements, the second surfaces of the second electrical contact being in electrical contact with and extending along the first surfaces of the plurality of second elements, the first contact and the second contact being disposed on opposite longitudinal surfaces of each of the plurality of first elements to provide for current flow through the plurality of first elements in a direction substantially transverse to an axis of the plurality of first elements; a third electrical contact being in electrical contact with the second surfaces of the plurality of second elements, the second contact and the third contact being disposed on opposite longitudinal surfaces of each of the plurality of second elements to provide for current flow through the plurality of second elements in a direction substantially transverse to an axis of the plurality of second elements; a reflector for the first band of infrared radiation and the second band of infrared radiation, the reflector being disposed on an opposite longitudinal surface of the third contact from the plurality of second elements, wherein the first period is an integer multiple of the second period.