Quantum Semiconductor LLC

Carlos J R P Augusto

Pedro N C Diniz

Lynn Forester

Photonic devices monolithically integrated with CMOS are disclosed, including sub-100 nm CMOS, with active layers comprising acceleration regions, light emission and absorption layers, and optional energy filtering regions. Light emission or absorption is controlled by an applied voltage to deposited films on a pre-defined CMOS active area of a substrate, such as bulk Si, bulk Ge, Thick-Film SOI, Thin-Film SOI, Thin-Film GOI.

CMOS pixels comprising epitaxial layers for light-sensing and light emission

Light guiding structures are provided to improve the light coupling between photonic active devices and the top of a metallization layer stack interconnecting these photonic active devices. Each light guiding structure comprises a hole extending between the near surface of the photonic active devices and the top surface of the metallization layer stack, said hole being filled with dielectrics or a combination of dielectrics and metals. Such a light guiding structure removes from the optical path of light rays, the interfaces between the metallization layers, thereby confining light laterally and enabling interconnects with increased thickness and more levels of metal. This results in the suppression of multiple reflections and optical crosstalk. The light guiding structures can have cross-section diagonals with sub-wavelength dimensions can be fabricated after all CMOS process steps, thus having minimal interference and maximal compatibility with CMOS processing.

Photonic via waveguide for pixel arrays

Photonic passive structure to couple and guide light between photonic active devices (), such as photo-diodes, light emitting devices and light-valves, which may be arranged into 2D arrays, and the top of the metallization layer stack () interconnecting said devices, with said photonic passive structure comprising a hole () between the near surface of said photonic active Ndevices and the top of said metallization stack, said hole being filled with a dielectric () having embedded metal films () and in which the embedded metal thin films are connected to a planar perforated metal film () formed on top of the metallization stack.

An epitaxial device module monolithically integrated with a CMOS structure in a bulk or thick-film SOI substrate, comprising an active area on which epitaxial layers are formed by selective or non-selective epitaxial growth and a separate active area in which the CMOS structure is formed. A hard mask for epitaxy having an opening therein provides self-alignment for optional ion implants into the substrate. The ion-implanted region overlaps the active region underneath the epitaxial layer, a portion of the source/drain region of the CMOS structure and the isolation region separating the two active areas, thereby establishing a conductive path underneath the isolation region between the two active areas.

Method of fabricating heterojunction photodiodes with CMOS

Imaging devices including a novel imaging system wherein a 2-dimensional pixel array has a diagonal dimension larger than the diameter measurement of the image circle, thereby being capable of handling rectangular images with multiple aspect ratios. These new imaging devices can be used in various electronic imaging apparatus with or without a lens system.

Imaging devices operable with multiple aspect ratios

A photo-current mode of operation is disclosed for Full Frame CCDs, and Frame-Transfer CCDs, that is suitable for electrical power generation, when not in operation for image sensing, and for Interline-Transfer CCDs, that is suitable for image sensing, and also suitable electrical power generation, when not in operation for image sensing. Further, CMOS Image Sensors (CIS), including 1T Passive Pixels, or 1T Avalanche Photo-Diode Pixels, in which all pass transistors in the matrix are turned ON simultaneously thereby allowing the photo-current produced by each photo-diode in each pixel to flow towards the periphery where suitable circuitry will handle the photo-current for electrical power generation and/or storage. Also, CMOS Image Sensors (CIS), including any Active Pixel Sensor (APS) design, such as the 3T, or 3T Log, or 4T, or 5T, wherein each column-parallel VDD line connecting the Reset Transistors, or the Log Transistors, in a single column of pixels, to column-parallel circuitry at the edge of the pixel matrix, is connected through multiple pass transistors, to different column-parallel blocks of circuitry that are selected alternatively, and that include (1) a VDD voltage source for standard image sensing operation, (2) a block of circuitry suitable to handle photo-current signals for image sensing purposes, and (3) a block of circuitry that is suitable to handle photo-current for electrical power generation and/or storage purposes.

Image sensors with photo-current mode and solar cell operation

Several detailed layout designs are disclosed, for the monolithic integration of avalanche devices in large arrays, that can be operated as Avalanche Photo-Diodes (APDs) or Avalanche Light Emitting Diodes (ALEDs) depending only on the applied bias conditions, which can be software-controlled from peripheral circuitry. If the deposited films have direct bandgaps, then the devices can emit light even in the absence of avalanche operation. In particular, the layouts according to the invention comprise a sensor/emitter matrix achieved through the replication of basic Pixel/Lixel cells.

Layouts for the monolithic integration of CMOS and deposited photonic active layers

A method of fabricating multi-spectral photo-sensors including photo-diodes incorporating stacked epitaxial superlattices monolithically integrated with CMOS devices on a common semiconductor substrate.

Light-sensing device for multi-spectral imaging

A method of fabricating light-sensing devices including photodiodes monolithically integrated with CMOS devices. Several types of photodiode devices (PIN, HIP) are expitaxially grown in one single step on active areas implanted in a common semiconductor substrate, the active areas having defined polarities. The expitaxially grown layers for the photodiode devices may be either undoped or in-situ doped with profiles suitable for their respective operation. With appropriate choice of substrate materials, device layers and heterojunction engineering and process architecture, it is possible to fabricate silicon-based and germanium-based multi-spectral sensors that can deliver pixel density and cost of fabrication comparable to the state of the art CCDs and CMOS image sensors. The method can be implemented with epitaxially deposited films on the following substrates: Silicon Bulk, Thick-Film and Thin-Film Silicon-On-Insulator (SOI), Germanium Bulk, Thick-Film and Thin-Film Geranium-On-Insulator (GeOI).

Light-sensing device

An analog-to-digital converter apparatus for analog source signals of one polarity, includes one comparator formed from transistors, a block of digitally addressable voltage sources to set a reference voltage of the comparator, an asynchronous n-bit digital counter, a block of digitally addressable voltage sources to set the potential to be applied to the signal source, a digital control unit, a block storing the calibration data for an input capacitor of the comparator, and a base-2 multiplier block, being interconnected by lines, including a line connecting the input analog signal to the drain of a pass transistor, a line connecting the block of voltage sources to be connected to the signal source, a line connecting the digital control unit to transistor gates, and a line carrying the signal Vref from the block of digitally addressed voltage sources to the comparator.

Multi-mode ADC and its application to CMOS image sensors

A device comprising a number of different wavelength-selective active-layers arranged in a vertical stack, having band-alignment and work-function engineered lateral contacts to said active-layers, consisting of a contact-insulator and a conductor-insulator. Photons of different energies are selectively absorbed in or emitted by the active-layers. Contact means are arranged separately on the lateral sides of the vertical stack for injecting charge carriers into the photon-emitting layers and extracting charge carriers generated in the photon-absorbing layers. The device can be used for various applications for light emission or light absorption. The stack of active layers may also include top and bottom electrodes whereby the device can also be operated as a FET device.

Wavelength selective photonics device

An analog-to-digital converter apparatus for analog source signals of one polarity, includes one comparator formed from transistors, a block of digitally addressable voltage sources to set a reference voltage of the comparator, an asynchronous n-bit digital counter, a block of digitally addressable voltage sources to set the potential to be applied to the signal source, a digital control unit, a block storing the calibration data for an input capacitor of the comparator, and a base-multiplier block, being interconnected by lines, including a line connecting the input analog signal to the drain of a pass transistor, a line connecting the block of voltage sources to be connected to the signal source, a line connecting the digital control unit to transistor gates, and a line carrying the signal Vref from the block of digitally addressed voltage sources to the comparator.

Light sensing devices are monolithically integrates with CMOS devices on Thin-Film Silicon-On-insulator (TF-SOI) or Thin-Film Germanium-On-Insulator (TF-GeOI) substrates. Photo-diode active layers are epitaxially grown on the front-side of the substrate and after full processing of the front-side of the substrate, the substrate material is removed under the buried insulator (buried oxide). Monolithically integrated structures are then fabricated on the back of the buried oxide. The back-side is then bonded to a new substrate that is transparent to the wavelengths of interest. For example, quartz, sapphire, glass, or plastic, are suitable for the visible range. Back-side illumination of the sensor matrix is thereby allowed, with light traveling through the structures fabricated on the back of the substrate, opposite to the side on which CMOS is made.

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San Jose, CA, United States of America

Carlos J R P Augusto