Abstract: In accordance with the invention, an improved image sensor comprises an array of germanium photosensitive elements integrated with a silicon substrate and integrated with silicon readout circuits. The silicon transistors are formed first on a silicon substrate, using well known silicon wafer fabrication techniques. The germanium elements are subsequently formed overlying the silicon by epitaxial growth. The germanium elements are advantageously grown within surface openings of a dielectric cladding. Wafer fabrication techniques are applied to the elements to form isolated germanium photodiodes. Since temperatures needed for germanium processing are lower than those for silicon processing, the formation of the germanium devices need not affect the previously formed silicon devices. Insulating and metallic layers are then deposited and patterned to interconnect the silicon devices and to connect the germanium devices to the silicon circuits.

Abstract: In accordance with the invention, an improved image sensor includes an array of germanium photosensitive elements integrated with a silicon substrate and integrated with silicon readout circuits. The silicon transistors are formed first on a silicon substrate, using well known silicon wafer fabrication techniques. The germanium elements are subsequently formed overlying the silicon by epitaxial growth. The germanium elements are advantageously grown within surface openings of a dielectric cladding. Wafer fabrication techniques are applied to the elements to form isolated germanium photodiodes. Since temperatures needed for germanium processing are lower than those for silicon processing, the formation of the germanium devices need not affect the previously formed silicon devices. Insulating and metallic layers are then deposited and patterned to interconnect the silicon devices and to connect the germanium devices to the silicon circuits.

Abstract: In accordance with the invention, an improved image sensor comprises an array of germanium photosensitive elements integrated with a silicon substrate and integrated with silicon readout circuits. The silicon transistors are formed first on a silicon substrate, using well known silicon wafer fabrication techniques. The germanium elements are subsequently formed overlying the silicon by epitaxial growth. The germanium elements are advantageously grown within surface openings of a dielectric cladding. Wafer fabrication techniques are applied to the elements to form isolated germanium photodiodes. Since temperatures needed for germanium processing are lower than those for silicon processing, the formation of the germanium devices need not affect the previously formed silicon devices. Insulating and metallic layers are then deposited and patterned to interconnect the silicon devices and to connect the germanium devices to the silicon circuits.

Abstract: A photodetector is formed from a body of semiconductor material substantially surrounded by dielectric surfaces. A passivation process is applied to at least one surface to reduce the rate of carrier generation and recombination on that surface. Photocurrent is read out from at least one electrical contact, which is formed on a doped region whose surface lies entirely on a passivated surface. Unwanted leakage current from un-passivated surfaces is reduced through one of the following methods: (a) The un-passivated surface is separated from the photo-collecting contact by at least two junctions; (b) The un-passivated surface is doped to a very high level, at least equal to the conduction band or valence band density of states of the semiconductor; (c) An accumulation or inversion layer is formed on the un-passivated surface by the application of an electric field.

Abstract: Optical imaging structures and methods are disclosed. One structure may be implemented as an imaging pixel having multiple photodetectors. The photodetectors may detect different wavelengths of incident radiation, and may be operated simultaneously or at separate times. An imager may include an imaging array of pixels of the type described. Methods of operating such structures are also described.

Abstract: In accordance with the invention, an improved image sensor includes an array of germanium photosensitive elements integrated with a silicon substrate and integrated with silicon readout circuits. The silicon transistors are formed first on a silicon substrate, using well known silicon wafer fabrication techniques. The germanium elements are subsequently formed overlying the silicon by epitaxial growth. The germanium elements are advantageously grown within surface openings of a dielectric cladding. Wafer fabrication techniques are applied to the elements to form isolated germanium photodiodes. Since temperatures needed for germanium processing are lower than those for silicon processing, the formation of the germanium devices need not affect the previously formed silicon devices. Insulating and metallic layers are then deposited and patterned to interconnect the silicon devices and to connect the germanium devices to the silicon circuits.

Abstract: An improved CMOS pixel with a combination of analog and digital readouts to provide a large pixel dynamic range without compromising low-light performance using a comparator to test the value of an accumulated charge at a series of exponentially increasing exposure times. The rest is used to stop the integration of photocurrent once the accumulated analog voltage has reached a predetermined threshold. A one-bit output value of the test is read out of the pixel (digitally) at each of the exponentially increasing exposure periods. At the end of the integration period, the analog value stored on the integration capacitor is read out using conventional CMOS active pixel readout circuits.

Abstract: Imaging arrays comprising at least two different imaging pixel types are described. The different imaging pixel types may differ in their light sensitivities and/or light saturation levels. Methods of processing the output signals of the imaging arrays are also described, and may produce images having a greater dynamic range than would result from an imaging array comprising only one of the at least two different imaging pixel types.

Abstract: Methods and apparatus are provided for performing multiple correlated double sampling (CDS) operations on an imaging pixel, and in some cases on an array of imaging pixels, during a single integration cycle of the pixel(s). The multiple CDS operations may produce multiple CDS values, which may be processed in combination to produce a resulting value substantially free of various types of noise. The CDS operations may be performed using a CDS circuit including a single-ended charge amplifier having an input capacitor. The charge amplifier may also include a variable capacitance providing a variable gain. The variable capacitance may be provided by a feedback capacitor.

Abstract: An improved CMOS pixel with a combination of analog and digital readouts to provide a large pixel dynamic range without compromising low-light performance using a comparator to test the value of an accumulated charge at a series of exponentially increasing exposure times. The test is used to stop the integration of photocurrent once the accumulated analog voltage has reached a predetermined threshold. A one-bit output value of the test is read out of the pixel (digitally) at each of the exponentially increasing exposure periods. At the end of the integration period, the analog value stored on the integration capacitor is read out using conventional CMOS active pixel readout circuits.

Abstract: Imagers, pixels, and methods of using the same are disclosed for imaging in various spectra, such as visible, near infrared (IR), and short wavelength IR (SWIR). The imager may have an imaging array having pixels of different types. The different types of pixels may detect different ranges of wavelengths in the IR, or the SWIR, spectra. The pixels may include a filter which blocks some wavelengths of radiation in the IR spectrum while passing other wavelengths. The filter may be formed of a semiconductor material, and therefore may be easily integrated with a CMOS pixel using conventional CMOS processing techniques.

Abstract: Methods and apparatus are provided for performing multiple correlated double sampling (CDS) operations on an imaging pixel, and in some cases on an array of imaging pixels, during a single integration cycle of the pixel(s). The multiple CDS operations may produce multiple CDS values, which may be processed in combination to produce a resulting value substantially free of various types of noise. The CDS operations may be performed using a CDS circuit including a single-ended charge amplifier having an input capacitor. The charge amplifier may also include a variable capacitance providing a variable gain. The variable capacitance may be provided by a feedback capacitor.

Abstract: An improved monolithic solid state imager comprises plural sub-arrays of respectively different kinds of pixels, an optional filter mosaic comprising color filters and clear elements, and circuitry to process the output of the pixels. The different kinds of pixels respond to respectively different spectral ranges. Advantageously the different kinds of pixels can be chosen from: 1) SWIR pixels responsive to short wavelength infrared (SWIR) in the range of approximately 800-1800 nm; 2) regular pixels responsive to visible and NIR radiation (400-1000 nm) and wideband pixels responsive to visible, NIR and SWIR radiation.

Abstract: Imagers, pixels, and methods of using the same are disclosed for imaging in various spectra, such as visible, near infrared (IR), and short wavelength IR (SWIR). The imager may have an imaging array having pixels of different types. The different types of pixels may detect different ranges of wavelengths in the IR, or the SWIR, spectra. The pixels may include a filter which blocks some wavelengths of radiation in the IR spectrum while passing other wavelengths. The filter may be formed of a semiconductor material, and therefore may be easily integrated with a CMOS pixel using conventional CMOS processing techniques.

Abstract: In accordance with the invention, an improved image sensor comprises an array of germanium photosensitive elements integrated with a silicon substrate and integrated with silicon readout circuits. The silicon transistors are formed first on a silicon substrate, using well known silicon wafer fabrication techniques. The germanium elements are subsequently formed overlying the silicon by epitaxial growth. The germanium elements are advantageously grown within surface openings of a dielectric cladding. Wafer fabrication techniques are applied to the elements to form isolated germanium photodiodes. Since temperatures needed for germanium processing are lower than those for silicon processing, the formation of the germanium devices need not affect the previously formed silicon devices. Insulating and metallic layers are then deposited and patterned to interconnect the silicon devices and to connect the germanium devices to the silicon circuits.

Abstract: Methods and apparatus are provided for performing multiple correlated double sampling (CDS) operations on an imaging pixel, and in some cases on an array of imaging pixels, during a single integration cycle of the pixel(s). The multiple CDS operations may produce multiple CDS values, which may be processed in combination to produce a resulting value substantially free of various types of noise. The CDS operations may be performed using a CDS circuit including a single-ended charge amplifier having an input capacitor. The charge amplifier may also include a variable capacitance providing a variable gain. The variable capacitance may be provided by a feedback capacitor.

Abstract: A photodetector is formed from a body of semiconductor material substantially surrounded by dielectric surfaces. A passivation process is applied to at least one surface to reduce the rate of carrier generation and recombination on that surface. Photocurrent is read out from at least one electrical contact, which is formed on a doped region whose surface lies entirely on a passivated surface. Unwanted leakage current from un-passivated surfaces is reduced through one of the following methods: (a) The un-passivated surface is separated from the photo-collecting contact by at least two junctions; (b) The un-passivated surface is doped to a very high level, at least equal to the conduction band or valence band density of states of the semiconductor; (c) An accumulation or inversion layer is formed on the un-passivated surface by the application of an electric field.

Abstract: An improved CMOS pixel with a combination of analog and digital readouts to provide a large pixel dynamic range without compromising low-light performance using a comparator to test the value of an accumulated charge at a series of exponentially increasing exposure times. The test is used to stop the integration of photocurrent once the accumulated analog voltage has reached a predetermined threshold. A one-bit output value of the test is read out of the pixel (digitally) at each of the exponentially increasing exposure periods. At the end of the integration period, the analog value stored on the integration capacitor is read out using conventional CMOS active pixel readout circuits.

Abstract: Imagers, pixels, and methods of using the same are disclosed for imaging in various spectra, such as visible, near infrared (IR), and short wavelength IR (SWIR). The imager may have an imaging array having pixels of different types. The different types of pixels may detect different ranges of wavelengths in the IR, or the SWIR, spectra. The pixels may include a filter which blocks some wavelengths of radiation in the IR spectrum while passing other wavelengths. The filter may be formed of a semiconductor material, and therefore may be easily integrated with a CMOS pixel using conventional CMOS processing techniques.

Abstract: Methods and apparatus are provided for performing multiple correlated double sampling (CDS) operations on an imaging pixel, and in some cases on an array of imaging pixels, during a single integration cycle of the pixel(s). The multiple CDS operations may produce multiple CDS values, which may be processed in combination to produce a resulting value substantially free of various types of noise. The CDS operations may be performed using a CDS circuit including a single-ended charge amplifier having an input capacitor. The charge amplifier may also include a variable capacitance providing a variable gain. The variable capacitance may be provided by a feedback capacitor.