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45 results about "Silicon on sapphire" patented technology
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Silicon on sapphire (SOS) is a hetero-epitaxial process for metal-oxide-semiconductor (MOS) integrated circuit (IC) manufacturing that consists of a thin layer (typically thinner than 0.6 µm) of silicon grown on a sapphire (Al₂O₃) wafer. SOS is part of the silicon-on-insulator (SOI) family of CMOS (complementary MOS) technologies. Typically, high-purity artificially grown sapphire crystals are used. The silicon is usually deposited by the decomposition of silane gas (SiH₄) on heated sapphire substrates. The advantage of sapphire is that it is an excellent electrical insulator, preventing stray currents caused by radiation from spreading to nearby circuit elements. SOS faced early challenges in commercial manufacturing because of difficulties in fabricating the very small transistors used in modern high-density applications. This is because the SOS process results in the formation of dislocations, twinning and stacking faults from crystal lattice disparities between the sapphire and silicon. Additionally, there is some aluminum, a p-type dopant, contamination from the substrate in the silicon closest to the interface.
Described is a method for making silicon on sapphire structures, and devices therefrom. The inventive method of forming integrated circuits on a sapphire substrate comprises the steps of providing a device layer on an oxide layer of a temporary substrate; bonding the device layer to a handling substrate; removing the temporary substrate to provide a structure containing the device layer between the oxide layer and the handling substrate; bonding a sapphire substrate to the oxide layer; removing the handling substrate from the structure; and annealing the final structure to provide a substrate comprising the oxide layer between the device layer and the sapphire substrate. The sapphire substrate may comprise bulk sapphire or may be a conventional substrate material with an uppermost sapphire layer.
An integrated photodetector means for controlling the output of a light source, where the control means is a photodetector formed on a silicon-on-insulator substrate. The integrated photodetector senses the optical power from the light source and provides an electrical feedback signal which can be used to adjust the DC bias levels of the light source control driver circuit. The approach readily lends itself to large arrays of light sources bonded to silicon-on-sapphire driver circuits and is especially suitable for controlling light sources such as VCSELs in arrays such as are found in communications systems.
A method for eliminating the radiation-induced off-state current in the P-channel ultrathin silicon-on-sapphiretransistor, by providing a retrograde dopant concentration profile that has the effect of moving the Fermi level at the back of the device away from that part of the bandgap where the interface states are located. When the Fermi level does not swing through this area in any region of operation of the device, subthreshold stretchout of the I-V curves does not occur.
Methods and systems for communicating via leaky wave antennas (LWAs) on high resistivity substrates are disclosed and may include communicating RF signals using one or more LWAs that may be integrated in an integrated circuit (chip) comprising a high resistivity substrate, which may include a silicon-on-sapphire substrate. The LWAs integrated in the chip may be configured to transmit the RF signals at a desired angle from the surface of the chip. The RF signals may be communicated between regions within the chip. The LWAs may include microstrip or coplanar waveguides where the cavity height of the one or more of the LWAs may be configured by controlling spacing between conductive lines in the waveguides. The RF signals may be communicated from the LWAs integrated in the chip to LWAs in a package to which the chip is bonded or in a printed circuit board to which the package is bonded.
A liquid crystal display includes: a) a sapphire substrate; b) a single crystalsilicon structure disposed on the sapphire substrate to create a silicon-on-sapphire structure; c) a plurality of liquid crystal capacitors disposed on the silicon-on-sapphire structure; d) integrated self-aligned circuitry formed from the crystal silicon structure, where the circuitry modulates the liquid crystal capacitors such that a video image is generated; and e) an integrated audio transducer disposed on the silicon-on-sapphire structure for generating an audible signal.
An advanced, back-illuminated, siliconavalanche photodiode (APD) design is presented using silicon-on-sapphire with a novel crystalline aluminum nitride (AlN) antireflective layer between the silicon and R-plane sapphire. The substrate supports optical and electrical integration of a high quantum efficiency silicon APD with a galliumnitride (GaN)-VCSEL diode in each pixel to form a novel, compact, emitter-detector pixel for passive and active 2-D and 3-D high resolution, imaging focal plane arrays. Silicon mesa pixels are anisotropically etched with a central inverted mesa frustum cavity. The APD detector is fabricated in the silicon mesa and the GaN-VCSEL diode is grown epitaxially in the center of the mesa. A sapphiremicrolens below each pixel collimates the VCSEL beam and focuses optical returns into the APD detector. APDs share a common front-side anode, and VCSELs share a common cathode. The APD cathode is electrically connected to the VCSEL diodeanode in each emitter-detector pixel.
A semiconductor device is created in a doped silicon layer at most one-tenth of a micrometer thick formed on and having an interface with a sapphire substrate. An oppositely doped source region is formed in the silicon layer. A gate electrode is formed above part of the silicon layer. A diffusion layer doped with the same type of impurity as the source region but at a lower concentration is formed in the silicon layer, extending into a first area beneath the gate electrode, functioning as a drain region or as a lightly-doped extension of a more heavily doped drain region. The depth of this diffusion layer is less than the thickness of the silicon layer. This comparatively shallow diffusion depth reduces current leakage by inhibiting the formation of a back channel.
A method for eliminating the radiation-induced off-state current in the P-channel ultrathin silicon-on-sapphiretransistor, by providing a retrograde dopant concentration profile that has the effect of moving the Fermi level at the back of the device away from that part of the bandgap where the interface states are located. When the Fermi level does not swing through this area in any region of operation of the device, subthreshold stretchout of the I-V curves does not occur.
A system for maintaining battery temperatures for energy storage systems using heat created by power electronic device needed to interface the batteries to external power sources or loads is described. Waste heat is a product of internal resistance found in all electronic devices passing current. High-temperature electronics comprised of, silicon-on-insulator, silicon-on-sapphire, silicon-carbide, gallium-nitride or in conjunction with or combination of other wide bandgap semiconductors can used to monitor, charge or discharge the battery array. A thermal system where heat generated by power electronics is used to assist the thermal management of battery energy storage system increases overall system efficiency.
A liquid crystal display includes: a) a sapphire substrate having a first crystal lattice structure; b) a single crystalsilicon structure having a thickness no greater than about 100 nanometers affixed to the sapphire substrate to create a silicon-on-sapphire structure, and a second crystal lattice structure oriented by the first crystal lattice structure; c) an array of liquid crystal capacitors formed on the silicon-on-sapphire structure; and d) integrated self-aligned circuitry formed from the silicon layer which is operably coupled to modulate the liquid crystal capacitors. The liquid crystals capacitors may include nematic or ferroelectric liquid crystal material.
A detector with a transistor sensitive to electromagnetic energy. In accordance with the present teachings, the transistor is biased such that the output thereof is responsive to the electromagnetic energy. The inventive imager includes an array of the novel detectors. Each of the detectors being an n-channel metal-oxidesemiconductortransistor with a floating body. The transistors are biased for selective activation and sequential readout. The transistor outputs are read by a differential current sense amplifier. A color filter is disclosed to provide a color sense capability. As an alternative, a grating is provided for this purpose. The present invention allows a very dense imager to be built on using conventional silicon on sapphire or silicon on insulator complementary metal-oxidesemiconductor processes. The use of standard CMOS processes allows for low manufacturing costs.
Quasi-phase matched (QPM), semiconductor photonic waveguides include periodically-poled alternating first and second sections. The first sections exhibit a high degree of optical coupling (abbreviated “X2”), while the second sections have a low X2. The alternating first and second sections may comprise high-strain and low-strain sections made of different material states (such as crystalline and amorphous material states) that exhibit high and low X2 properties when formed on a particular substrate, and / or strained corrugated sections of different widths. The QPM semiconductor waveguides may be implemented as silicon-on-insulator (SOI), or germanium-on-silicon structures compatible with standard CMOS processes, or as silicon-on-sapphire (SOS) structures.
A resistivity tool includes receiverelectronics near each receiver antenna loop. Placement of the electronics in this position such as at the circuit card between the terminal ends of the receiver antenna loop improves signal to noise ratio by reducing or eliminating interference, noise, and cross-talk of transmissions from the receiver to a remote microprocessor. By using material such as silicon-on-sapphire, electronics can be miniaturized and operate reliably at when exposed to high temperatures, even for long periods.
A DC-DC converter includes an insulating substrate; a magnetic core embedded in the insulating substrate, the magnetic core having non-zero x, y and z dimensions of less than or equal to about 5.4 mm by about 5.4 mm by about 1.8 mm; separate primary and secondary transformer windings surrounding first and second regions of the magnetic core; and a control circuit including: an oscillator; a drive circuit coupled to the oscillator; and one or more switches coupled to the drive circuit; the drive circuit providing a switching signal to the one or more switches and energizing the one or more switches to provide a drive voltage to the primary transformer winding. The one or more switches are Field Effect Transistors implemented in a Silicon-on-Insulator configuration or as a Silicon-on-Sapphire configuration.
An advanced, back-illuminated, siliconavalanche photodiode (APD) design is presented using silicon-on-sapphire with a novel crystalline aluminum nitride (AlN) antireflective layer between the silicon and R-plane sapphire. The substrate supports optical and electrical integration of a high quantum efficiency silicon APD with a galliumnitride (GaN)-VCSEL diode in each pixel to form a novel, compact, emitter-detector pixel for passive and active 2-D and 3-D high resolution, imaging focal plane arrays. Silicon mesa pixels are anisotropically etched with a central inverted mesa frustum cavity. The APD detector is fabricated in the silicon mesa and the GaN-VCSEL diode is grown epitaxially in the center of the mesa. A sapphiremicrolens below each pixel collimates the VCSEL beam and focuses optical returns into the APD detector. APDs share a common front-side anode, and VCSELs share a common cathode. The APD cathode is electrically connected to the VCSEL diodeanode in each emitter-detector pixel.
A method for eliminating the radiation-induced off-state current in the P-channel ultrathin silicon-on-sapphiretransistor, by providing a retrograde dopant concentration profile that has the effect of moving the Fermi level at the back of the device away from that part of the bandgap where the interface states are located. When the Fermi level does not swing through this area in any region of operation of the device, subthreshold stretchout of the I-V curves does not occur.
A silicon-on-insulator metaloxidesemiconductor device comprising ultrathin silicon-on-sapphire substrate; at least one P-channel MOS transistor formed in the ultrathin silicon layer; and N-type impurity implanted within the ultrathin silicon layer and the sapphire substrate such that peak N-type impurity concentration in the sapphire layer is greater than peak impurity concentration in the ultrathin silicon layer.