Germanium-based sensors are disclosed herein. An exemplary germanium-based sensor includes a germanium photodiode and a junction field effect transistor (JFET) formed from a germanium layer disposed on and/or in a silicon substrate. A doped silicon layer, which can be formed by in-situ doping epitaxially grown silicon, is disposed between the germanium layer and the silicon substrate. In embodiments where the germanium layer is on the silicon substrate, the doped silicon layer is disposed between the germanium layer and an oxide layer. The JFET has a doped polysilicon gate, and in some embodiments, a gate diffusion region is disposed in the germanium layer under the doped polysilicon gate. In some embodiments, a pinned photodiode passivation layer is disposed in the germanium layer. In some embodiments, a pair of doped regions in the germanium layer is configured as an e-lens of the germanium-based sensor.

An image capturing device is provided. The device comprises a photodiode including a first semiconductor region of a first conductivity type and a second semiconductor region of a second conductivity type, a third semiconductor region of the second conductivity type, an insulator arranged between the photodiode and the third semiconductor region and a channel stop region of the first conductivity type which covers a side and a bottom surface of the insulator. The channel stop region includes a fourth semiconductor region arranged between the insulator and the second semiconductor region and a fifth semiconductor region arranged between the insulator and the third semiconductor region. An impurity concentration in the fourth semiconductor region is higher than an impurity concentration in the fifth semiconductor region and the impurity concentration in the fifth semiconductor region is not less than an impurity concentration in the first semiconductor region.

Provided are a light-receiving element which has more capability of detecting wavelengths than that of existing silicon light-receiving elements and a unit pixel of an image sensor by using it. The light-receiving element includes: a light-receiving unit which is floated or connected to external voltage and absorbs light; an oxide film which is formed to come in contact with a side of the light-receiving unit; a source and a drain which stand off the light-receiving unit with the oxide film in between and face each other; a channel which is formed between the source and the drain and forms an electric current between the source and the drain; and a wavelength expanding layer which is formed in at least one among the light-receiving unit, the oxide film and the channel and forms a plurality of local energy levels by using strained silicon.

Some embodiments provide an image sensor pixel comprising a junction field effect transistor (JFET) and a floating diffusion configured to act as the gate of the JFET. An image sensor may comprise a plurality of pixels, at least one pixel comprising a floating diffusion region formed in a semiconductor substrate, a transfer gate configured to selectively cause transfer of photocharge stored in the pixel to the floating diffusion, and a JFET having (i) a source and a drain coupled by a channel region, and (ii) a gate comprising the floating diffusion region.

A precursor cell for a transistor having a foundation structure, a mask structure, and a gallium nitride (GaN) PN structure is provided. The mask structure is provided over the foundation structure to expose a first area of a top surface of the foundation structure. The GaN PN structure resides over the first area and at least a portion of the mask structure and has a continuous crystalline structure with no internal regrowth interfaces. The GaN PN structure comprises a drift region over the first area, a control region laterally adjacent the drift region, and a PN junction formed between the drift region and the control region. Since the drift region and the control region form the PN junction having no internal regrowth interfaces, the GaN PN structure has a continuous crystalline structure with reduced regrowth related defects at the interface of the drift region and the control region.

A method of fabricating asymmetric vertical field effect transistors (VFETs) includes forming mandrels above a substrate comprising a first semiconductor material. A first set of spacers is formed adjacent to each side of the mandrels, and trenches are formed in portions of the substrate that are not below one of the mandrels or one of the first set of spacers. The method also includes filling the trenches with a second semiconductor material that is different from the first semiconductor material and forming a second set of spacers adjacent to each respective one of the first set of spacers. The second set of spacers is above the second semiconductor material. A plurality of fins is formed such that each one of the plurality of fins includes a portion of the substrate and a portion of the second semiconductor material. Gates are formed between each adjacent pair of fins.

A photodiode pixel structure for imaging short wave infrared (SWIR) and visible light built in a planar structure and may be used for one dimensional and two dimensional photodiode arrays. The photodiode arrays may be hybridized to a read out integrated circuit (ROIC), for example, a silicon complementary metal-oxide-semiconductor (CMOS) circuit. The photodiode in each pixel is buried under the surface and does not directly contact the ROIC amplification circuit. Disconnecting the photodiode from the ROIC amplification circuit enables low dark current as well as double correlated sampling in the pixel.

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 precursor cell for a transistor having a foundation structure, a mask structure, and a gallium nitride (GaN) PN structure is provided. The mask structure is provided over the foundation structure to expose a first area of a top surface of the foundation structure. The GaN PN structure resides over the first area and at least a portion of the mask structure and has a continuous crystalline structure with no internal regrowth interfaces. The GaN PN structure comprises a drift region over the first area, a control region laterally adjacent the drift region, and a PN junction formed between the drift region and the control region. Since the drift region and the control region form the PN junction having no internal regrowth interfaces, the GaN PN structure has a continuous crystalline structure with reduced regrowth related defects at the interface of the drift region and the control region.

A solid-state imaging device includes a plurality of pixels, each of the plurality of pixels including a photoelectric converter. The photoelectric converter includes a first semiconductor region of a first conductivity type, a second semiconductor region of a second conductivity type provided under the first semiconductor region, and a third semiconductor region of the first conductivity type provided under the second semiconductor region. The second semiconductor region has a first end portion and a second end portion opposing to the first end portion. The third semiconductor region has a first region and a second region overlapping with the second semiconductor region in a plan view, and the first region and the second region are spaced apart from each other from a part of the first end portion to a part of the second end portion.