摘要:
Alternate layers of wide band gap and narrow band gaps of different kinds of semiconductors are used to form multiple channels of a FET. The channels are doped or formed as 2-DEG/2-DHG in narrow band semiconductor by charge supply layer in the wide band gap semiconductor. The different kinds of semiconductors form heterojunctions to confine the electrons/holes in separate thin spikes layers. A number of spikes (3–10 nm thick) of different doped or 2-DEG/2-DHG concentrations in various channels can result in overall electron concentration gradient such as a 1/x3 electron/hole concentrations profile. Such an electron/hole concentration gradient can result in a linear variation of drain current with voltage to obtain a wide dynamic range.
摘要:
This invention describes an approach for monolithically integrating all the components of a photoreceiver—optical amplifier, optical band-pass filter, and photodiode module—on a single chip. The photoreceiver array employs unique optical amplifier and conversion technologies that provides the ultra-sensitivity required for free space optical communications networks. As an example, by monolithically integrating a vertical cavity surface emitting laser-diode (VCSEL) optical preamplifier with a photodiode receiver and related amplifiers and filters on the same chip, sensitivities as low as −47 dBm (62 photons/bit at 2.5 Gb/s), along with an order of magnitude reduction in size, weight, and power consumption over comparable commercial-off-the-shelf (COTS) components can be demonstrated. In accordance with another aspect of the present invention, the concept of monolithic integration of optical amplifier with photodetector is extended to lasers, another amplifier and modulators covering ultra violet to very long wavelength infrared using the InP, GaAs, GaSb, InAs, InSb, SiGe, SiC and GaN etc based technologies.
摘要:
A vertical cavity semiconductor optical photoamplifer (VCSOA) is used as a modulating retro-reflector (MRR) as a pixel in an array. The boundary of the cavity in the VCSOA forms a mirror for reflecting an incident light as an amplified output.
摘要:
A high frequency amplifying device comprises a field effect transistor-bipolar transistor darlington pair. Such a device combines the main desirable features of both field effect transistors and bipolar transistors, therefore, having a high input impedance that is typical of FETs and a high transconductance (or high current gain) which is typical of bipolar transistors.
摘要:
A method of forming a semiconductor device having a non-alloyed contact layer. An active region is formed in a substrate and the non-alloyed contact layer is formed in the active region, the barrier height of source and drain electrodes for the non-alloyed contact layer being lower than the barrier height of the source and drain electrodes for the active region or the substrate. The preferred method of forming the non-alloyed contact layer is high dose implantation of an element selected in accordance with the substrate material. For example, if the substrate is GaAs the non-alloyed contact layer is formed by implanting In, and if the substrate is InP the non-alloyed contact layer is formed by implanting As or Sb.
摘要:
An InP MESFET having a semiconductor surface barrier layer formed of GaInP or AlInP. The semiconductor surface barrier layer is formed between an active layer and a gate electrode and the barrier height of the gate for the semiconductor surface barrier layer is higher than the barrier height of the gate for InP. In a method of forming an InP MESFET according to the present invention, the semiconductor surface barrier layer is formed by high dose implantation of Ga or Al into the active region. Surface barrier layers formed of other compounds, for example GaInAsP or AlInAsP, which have a lattice match with InP can be formed by other methods such as epitaxial growth.
摘要:
A process to fabricate a specified height and cross-section of Microwave Monolithic Integrated Circuit gold posts comprising a patterned conductive substrate overlayed by an adhesive layer, a matrix layer, and a photoresist layer. Using photolithographic techniques, gold post locations are defined in the photoresist layer. m Gold post locations and cross-sections are defined in the matrix layer. The adhesive layer at the gold post locations is removed. The gold post locations are plated to form gold posts. The matrix is etched and the adhesive is dissolved.
摘要:
A phosphor is placed on a light emitting surface of a solid state optical source. The phosphor absorbs the narrow bandwidth light from the optical source, and emits light that has a wide bandwidth. A lens is used to collect and focus the wide bandwidth light.
摘要:
A method for making a heterojunction bipolar transistor in which the collector (46) is epitaxially grown on the subcollector layer (36) through a hole (42) formed in a layer of insulating material (40) deposited on the subcollector layer (36). A base (48) is epitaxially grown on the collector (46). Because of unequal lateral and vertical growth rates, the peripheral region of the base extends over the layer of insulating material. The n and n.sup.+ layers (50, 52) of the second type of semiconducting material are sequentially grown on the base and an n.sup.+ layer (54) of the first type of semiconducting material is grown on the sequentially grown layers (50, 52). The n.sup.+ layer (54) and the sequentially grown layer (50, 52) are etched to form an emitter mesa over the collector (46) leaving exposed the peripheral portion of the base (48) extending over the layer of insulating material surrounding the hole (42). Metallic electrodes (62, 64 and 68) are then deposited which electrically contact the base (48), the emitter (54) and the subcollector (36).
摘要:
A high frequency amplifying device comprises a field effect transistor-bipolar transistor darlington pair. Such a device combines the main desirable features of both field effect transistors and bipolar transistors, therefore, having a high input impedance that is typical of FETs and a high transconductance (or high current gain) which is typical of bipolar transistors.