A quantum well infrared photodetector (QWIP) and method of making is disclosed. The QWIP includes a plurality of epi-layers formed into multiple periods of quantum wells, each of the quantum wells being separated by a barrier, the quantum wells and barriers being formed of II-VI semiconductor materials. A multiple wavelength QWIP is also disclosed and includes a plurality of QWIPs stacked onto a single epitaxial structure, in which the different QWIPs are designed to respond at different wavelengths. A dual wavelength QWIP is also disclosed and includes two QWIPs stacked onto a single epitaxial structure, in which one QWIP is designed to respond at 10 m and the other at 3-5 m wavelengths.

Embodiments described herein relate to a dual-band photodetector. The dual-band photodetector includes a barrier layer (10) disposed between two infrared absorption layers (8, 12) wherein the barrier layer (10) is lattice matched to at least one of the infrared absorption layers (8, 12). Furthermore, one infrared absorption layer includes dilute nitride to adjust the band gap to a desired cut-off wavelength while maintaining valence-band alignment with the barrier layer. Embodiments also relate to a system and processes for producing the photodetector fabricated from semiconductor materials.

An improvement is achieved in the performance of a semiconductor device. A semiconductor device includes an n.sup.-type semiconductor region formed in a p-type well, an n-type semiconductor region formed closer to a main surface of a semiconductor substrate than the n.sup.-type semiconductor region, and a p.sup.-type semiconductor region formed between the n.sup.-type semiconductor region and the n-type semiconductor region. A net impurity concentration in the n.sup.-type semiconductor region is lower than a net impurity concentration in the n-type semiconductor region. A net impurity concentration in the p.sup.-type semiconductor region is lower than a net impurity concentration in the p-type well.

A photo-sensing unit including a first electrode, a first insulation layer, a photo-sensing structure and a second electrode is provided. The first insulation layer covers the first electrode and has an opening exposing the first electrode. The photo-sensing structure is located on the first electrode and disposed in the opening of the first insulation layer. The photo-sensing structure includes a first photo-sensing layer and a second photo-sensing layer stacked with each other. A material of the first photo-sensing layer is Si.sub.xGe.sub.yO.sub.z. A material of the second photo-sensing layer is Si.sub.vO.sub.w. The second electrode covers the photo-sensing structure. A photo-sensing apparatus including the photo-sensing unit and a fabricating method of a photo-sensing unit are also provided.

A two-terminal detector has a back-to-back p/n/p SWIR/MWIR stack structure, which includes P-SWIR absorber, N-SWIR, wide bandgap bather, N-MWIR absorber, and P-MWIR layers, with contacts on the P-MWIR and P-SWIR layers. The junction between the SWIR layers and the junction between the MWIR layers are preferably passivated. The detector stack is preferably arranged such that a negative bias applied to the top of the stack reverse-biases the MWIR junction and forward-biases the SWIR junction, such that the detector collects photocurrent from MWIR radiation. A positive bias forward-biases the MWIR junction and reverse-biases the SWIR junction, such that photocurrent from SWIR radiation is collected. A larger positive bias induces electron avalanche at the SWIR junction, thereby providing detector sensitivity sufficient to provide low light level passive amplified imaging. Detector sensitivity in this mode is preferably sufficient to provide high resolution 3-D eye-safe LADAR imaging.

A photodiode structure is based on the use of a double junction sensitive to different wavelength bands based on a magnitude of a reverse bias applied to the photodiode. The monolithic integration of a sensor with double functionality in a single chip allows realization of a low cost ultra-compact sensing element in a single packaging useful in many applications which require simultaneous or spatially synchronized detection of optical photons in different spectral regions.

A low noise infrared photodetector has an epitaxial heterostructure that includes a photodiode and a transistor. The photodiode includes a high sensitivity narrow bandgap photodetector layer of first conductivity type, and a collection well of second conductivity type in contact with the photodetector layer. The transistor includes the collection well, a transfer well of second conductivity type that is spaced from the collection well and the photodetector layer, and a region of first conductivity type between the collection and transfer wells. The collection well and the transfer well are of different depths, and are formed by a single diffusion.

A dual-band infrared detector is provided. The dual-band infrared detector includes a first absorption layer sensitive to radiation in only a short wavelength infrared spectral band, and a barrier layer coupled to the first absorption layer. The barrier layer is fabricated from an alloy including aluminum and antimony, and at least one of gallium or arsenic. The dual-band infrared detector also includes a second absorption layer coupled to the barrier layer opposite the first absorption layer. The second absorption layer is sensitive to radiation in only a medium wavelength infrared spectral band. The composition of the alloy used to fabricate the barrier layer is selected such that valence bands of the barrier layer and the first and second absorption layers substantially align.

An infrared detector is provided. The infrared detector includes an absorption layer sensitive to radiation in only a short wavelength infrared spectral band, and a barrier layer coupled to the absorption layer. The barrier layer is fabricated from an alloy including aluminum and antimony, and at least one of gallium or arsenic, and the composition of the alloy is selected such that valence bands of the absorption layer and the barrier layer substantially align.

A monolithic Opto-MOSFET relay and manufacturing method thereof are provided. The manufacturing method of the monolithic Opto-MOSFET relay involves using a low ion doping concentration substrate. In this method, a first P-N junction structure, a second P-N junction structure, and an N-P-N junction structure are formed within an epitaxial layer. Dry etching is employed to divide the epitaxial layer into a high-voltage region and a low-voltage region, which are electrically isolated from the each other. Subsequently, an isolation layer is deposited on the epitaxial layer, and photomask etching is performed to generate multiple patterns. A metal layer is then deposited to form a light emitting diode (LED) based on the pattern within the first P-N junction structure, a photodiode within the second P-N junction structure, and at least one MOSFET within the N-P-N junction structure.