95 results about "Modulation doping" patented technology

Nano-engineered structures are disclosed, incorporating nanowhiskers of high mobility conductivity and incorporating pn junctions. In one embodiment, a nanowhisker of a first semiconducting material has a first band gap, and an enclosure comprising at least one second material with a second band gap encloses said nanoelement along at least part of its length, the second material being doped to provide opposite conductivity type charge carriers in respective first and second regions along the length of the of the nanowhisker, whereby to create in the nanowhisker by transfer of charge carriers into the nanowhisker, corresponding first and second regions of opposite conductivity type charge carriers with a region depleted of free carriers therebetween. The doping of the enclosure material may be degenerate so as to create within the nanowhisker adjacent segments having very heavy modulation doping of opposite conductivity type analogous to the heavily doped regions of an Esaki diode. In another embodiment, a nanowhisker is surrounded by polymer material containing dopant material. A step of rapid thermal annealing causes the dopant material to diffuse into the nanowhisker. In a further embodiment, a nanowhisker has a heterojunction between two different intrinsic materials, and Fermi level pinning creates a pn junction at the interface without doping.

A photon detector is obtained by using the intersubband absorption mechanism in a modulation doped quantum well(s). The modulation doping creates a very high electric field in the well which enables absorption of input TE polarized light and also conducts the carriers emitted from the well into the modulation doped layer from where they may recombine with carriers from the gate contact. Carriers are resupplied to the well by the generation of electrons across the energy gap of the quantum well material. The absorption is enhanced by the use of a resonant cavity in which the quantum well(s) are placed. The absorption and emission from the well creates a deficiency of charge in the quantum well proportional to the intensity of the input photon signal. The quantity of charge in the quantum well of each detector is converted to an output voltage by transferring the charge to the gate of an output amplifier. The detectors are arranged in the form of a 2D array with an output amplifier associated with the entire array or a row of the array as in the known charge coupled devices, or a separate amplifier could be dedicated to each pixel as in the known architecture of the active pixel device. This detector has the unique advantage of near room temperature operation because the dark current is limited to the generation across the semiconductor bandgap and not the emission over the quantum well barrier. The detector also has the advantage that the readout circuitry is implemented monolithically by the HFETs formed in the GaAs substrate simultaneously, with the detecting elements.

An improved heterostructure for an optoelectronic device is provided. The heterostructure includes an active region, an electron blocking layer, and a p-type contact layer. The p-type contact layer and electron blocking layer can be doped with a p-type dopant. The dopant concentration for the electron blocking layer can be at most ten percent the dopant concentration of the p-type contact layer. A method of designing such a heterostructure is also described.

The invention discloses a single crystal graphene pn node and a preparation method thereof. The modulated and doped graphene pn node is prepared according to the method which comprises the following steps of 1, annealing a copper foil substrate; 2, growing a sub-monolayer intrinsic graphene island on the surface of a copper foil by taking methane as a carbon source; 3, cleaning a growing system by using inert gas; 4, taking acetonitrile steam as a nitrogen-containing carbon source and growing nitrogen doped graphene on the boundary of the intrinsic graphene island; 5, repeating the steps 2, to 4, for at least zero time to obtain the single-level or multi-level graphene pn node; 6, quickly reducing the temperature to stop a growing process; and 7, transferring the graphene pn node which is obtained through modulating, doping and growing onto any target substrate by using polymethyl methacrylate (PMMA) as a medium. The modulated and doped graphene pn node with high quality is obtained by regulating the carbon source in the graphene growing process. The product has very high migration rate and photon to current conversion efficiency; and a transfer characteristic curve of the product has a double-Dirac point, so that the single crystal graphene pn node can be applied to logic devices, such as a phase inverter and a frequency multiplier.

A silicon and silicon germanium based semiconductor MODFET device design and method of manufacture. The MODFET design includes a high-mobility layer structure capable of ultra high-speed, low-noise for a variety of communication applications including RF, microwave, sub-millimeter-wave and millimeter-wave. The epitaxial field effect transistor layer structure includes critical (vertical and lateral) device scaling and layer structure design for a high mobility strained n-channel and p-channel transistor incorporating silicon and silicon germanium layers to form the optimum modulation-doped heterostructure on an ultra thin SOI or SGOI substrate capable of achieving greatly improved RF performance.

A normally-off type field-controlled channel GaN heterojunction diode belongs to the technical field of semiconductor devices. The invention adopts the technology of combining insulating layer-groove, modulation doping and groove-modulation doping to change the conductive channel structure of the existing GaN heterojunction diode, and convert the original normally-on spontaneously polarized GaN heterojunction The junction conductive channel is changed into a normally-off field-controlled conductive channel combining spontaneous polarization and piezoelectric polarization in the present invention, which realizes the field-controlled characteristics of the GaN heterojunction diode conductive channel and reduces the forward conduction resistance and enhanced reverse cut-off capability. The invention has lower forward conduction resistance and power consumption, stronger reverse cut-off ability, and is compatible with AlGaN/GaN HEMT power switching device technology, which is beneficial to the application of the device.

A repeatable and uniform low doped layer is formed using modulation doping by forming alternating sub-layers of doped and undoped nitride semiconductor material atop another layer. A Schottky diode is formed of such a low doped nitride semiconductor layer disposed atop a much more highly doped nitride semiconductor layer. The resulting device has both a low on-resistance when the device is forward biased and a high breakdown voltage when the device is reverse biased.

The invention discloses a III-group nitride light-emitting diode (LED) and a manufacturing method thereof. The LED comprises a substrate and a semiconductor epitaxial laminate which is laminated on the substrate, wherein the semiconductor epitaxial laminate sequentially comprises an N type layer, a luminescent layer and a P type layer from top to bottom. The LED is characterized in that: an N type layer table face is formed in the N type layer by etching a part of the semiconductor epitaxial laminate; an N type electrode is arranged on the N type layer table face; a P type electrode is arranged on the upper surface of the un-etched part of the P type layer; the N type layer also comprises a uniformly doped layer of which the doping concentration is consistent and a modulation doped layer of which the doping concentration is changeable; and the modulation doped layer is arranged between the uniformly doped layer and the luminescent layer. A doped mode of the modulation doped layer is gradual transition doping which connects uniformly doped layer and the luminescent layer of which the doping concentration is consistent. The concentration change trend is decrease progressively change from the uniformly doped layer to the luminescent layer. By the LED and the manufacturing method, the crystal quality and the luminance uniformity can be obviously improved, and the lighting effect is improved.

The invention discloses a preparing method for strained germanium, belonging to the field of semiconductor substrate preparation. Single crystal silicon buffer layer is deposited on a silicon substrate; the single crystal silicon buffer layer is covered with a strained single crystal silicon germanium Si1-Gex layer having a thickness less than the critical thickness, then oxidized, and converted into a relax high-germanium component Si1-yGey layer; the high-germanium component Si1-yGey layer is completely relaxed by ion injection and annealing, and covered with compression-strained germanium layer or compression-strained high-germanium component Si1-zGez layer, or the compression-strained germanium layer or compression-strained high-germanium component Si1-zGez layer is covered with tension-strained silicon layer or tension-strained Si1-aGea layer. The method can be used for manufacturing complementary metal oxide semiconductor, modulation-doped field effect transistor, high electron mobility transistor, bipolar transistor and other high-speed devices, and greatly improves the performance of the devices.

A structure and a method are disclosed of an enhanced T-gate for modulation doped field effect transistors (MODFETs). The enhanced T-gate has insulator spacer layers sandwiching the neck portion of the T-gate. The spacer layers are thinner than the T-bar portion overhang. The insulating layer provides mechanical support and protects the vulnerable neck portion of the T-gate from chemical attack during subsequent device processing, making the T-gate structure highly scalable and improving yield. The use of thin conformal low dielectric constant insulating layers ensures a low parasitic gate capacitance, and reduces the risk of shorting gate and source metallurgy when source-to-gate spacings are reduced to smaller dimensions.

An improved heterostructure for an optoelectronic device is provided. The heterostructure includes an active region, an electron blocking layer, and a p-type contact layer. The p-type contact layer and electron blocking layer can be doped with a p-type dopant. The dopant concentration for the electron blocking layer can be at most ten percent the dopant concentration of the p-type contact layer. A method of designing such a heterostructure is also described.

Embodiments of an apparatus and methods for providing three-dimensional complementary metal oxide semiconductor devices comprising modulation doped transistors are generally described herein. Other embodiments may be described and claimed.

The invention relates to a method for using MOCVD to grow nitride light emitting diode extensive plate, wherein said growing P-AlGaN carrier baffle layer uses modulated doping growing. The invention can reduce the positive operation voltage of nitride light emitting diode that extending growing, to improve the turn-on voltage and strengthen the breakdown reverse voltage.

A negative resistance field-effect element that is a negative differential resistance field-effect element capable of achieving negative resistance at a low power supply voltage (low drain voltage) and also enabling securement of a high PVCR is formed on its InP substrate 11 having an asymmetrical V-groove whose surface on one side is a (100) plane and surface on the other side is a (011) plane with an InAlAs barrier layer (12) that has a trench (TR) one of whose opposed lateral faces is a (111) A plane and the other of which is a (331) B plane. An InGaAs quantum wire (13) that has a relatively narrow energy band gap is formed at the trench bottom surface as a high-mobility channel. An InAlAs modulation-doped layer (20) having a relatively wide energy band gap is formed on the quantum wire as a low-mobility channel. A source electrode (42) and a drain electrode (43) each in electrical continuity with the quantum wire (13) constituting the high-mobility channel through a contact layer (30) and extending in the longitudinal direction of the quantum wire (13) as spaced from each other, and a gate electrode (41) provided between the source electrode (42) and the drain electrode (43) to face the low-mobility channel (20) through an insulating layer or a Schottky junction, are provided. Owing to the foregoing configuration, a very narrow-width quantum wire whose lateral confinement size can, without restriction by the lithographic technology limit, be made 100 nm or less is usable as a high-mobility channel, whereby there can be obtained a negative resistance field-effect element that develops a negative characteristic at a low power supply voltage and enables securement of a high PVCR.

The invention relates to a manufacturing method of a modulation-doped gallium nitride series light-emitting diode. The manufacturing method comprises the following steps of: step 1, preparing a substrate; step 2, manufacturing a gallium nitride nucleating layer and a gallium nitride buffer layer in sequence on the substrate; step 3, manufacturing an n-type gallium nitride contact layer on the gallium nitride buffer layer, and taking silane as an n-type doping agent; step 4, manufacturing an n-type current expanding layer, an active luminous layer, a p-type electronic blocking layer and a p-type contact layer in sequence on the upper surface of the n-type contact layer, which is not etched; step 5, etching the upper side of the p-type contact layer downwards with the etching depth reaching into the n-type gallium nitride contact layer by adopting an etching method to so that a platform surface is formed at one side of the n-type gallium nitride contact layer; and step 6, manufacturing a negative electrode on the platform surface of the n-type contact layer; and finally manufacturing a positive electrode on the p-type contact layer.

Apparatus and method for estimating a property of a downhole fluid including a carrier that is conveyed in a borehole, and a semiconductor electromagnetic energy source carried by the carrier, the semiconductor electromagnetic energy source having an active region that includes one or more nitride-based barrier layers that are modulation-doped using a nitride-based doped layer.

An improved heterostructure for an optoelectronic device is provided. The heterostructure includes an active region, an electron blocking layer, and a p-type contact layer. The p-type contact layer and electron blocking layer can be doped with a p-type dopant. The dopant concentration for the electron blocking layer can be at most ten percent the dopant concentration of the p-type contact layer. A method of designing such a heterostructure is also described.

A method for making a semiconductor heterostructure in a growth chamber with gas inlet comprises several steps. In a first step, a virtual substrate is formed on a silicon substrate, comprising a graded Si_1-xGe_x layer followed by a Si_1-xGe_x layer with constant concentration of Ge, using a high-density, low-energy plasma enhanced chemical vapor deposition (LEPECVD) process. In this step, the growth rate is maintained above 2 nm/s. the substrate temperature between 400° and 850° C., and the total reactive gas flow at the gas inlet between 5 sccm and 200 sccm. In another step, an active region is formed on said virtual substrate comprising a Ge-channel and a modulation-doped layer using a low-density, low-energy plasma enhanced chemical vapor deposition (LEPECVD) process. In this step, hydrogen (H₂) is introduced into the growth chamber to act as a surfactant, a substrate temperature is maintained between 400° and 500° C. and a dopant gas is introduced in a pulsed manner into the growth chamber to provide for the modulation-doped layer.