Abstract:
A fabrication method of a semiconductor device is disclosed. A T-shaped gate used for decreasing the gate resistance is adopted in fabricating an ultrahigh frequency and low-noise device. According to the present invention, a gate pattern is formed by a dual exposure technique, a thin metal film is formed, a pattern for plating is formed, and a gate is formed by electroplating, whereby decreasing a gate length and gate resistance. Therefore, the cost of production is decreased, the yield is improved, and the noise figure is minimized.
Abstract:
A method for isolating a semiconductor device is disclosed including the steps of sequentially growing a plurality of material layers on a semiconductor substrate, etching the material layers down to a predetermined depth of the substrate to thereby define an active region, forming a semi-insulating film on the exposed semiconductor substrate in order to planarize the step-difference of the active region and the isolation region, and then, forming an ohmic metal layer on a space where the semi-insulating film is regrown.
Abstract:
The invention relates to a method for manufacturing a super self-aligned heterojunction bipolar transistor which is capable of miniaturizing an element, simplifying the process step thereof by employing a selective collector epitaxial growth and a polycide base electrode without using a trench for isolating between elements, thereby enhancing the performance thereof, which comprises the steps of: forming sequently a first oxidation film, an electrically conducting thin film and a second oxidation film on top of a substrate; patterning the second oxidation film and the conducting thin film to form a preliminary spacer; removing an exposed portion of the first oxidation film, and selectively growing a collector layer; oxidizing the collector layer to form a thermal oxidation film, and removing the preliminary spacer; depositing a polysilicon and forming a silicon oxidation film and a polysilicon spacer on the second oxidation film and the removed portion of the preliminary spacer, respectively; exposing the base thin film, the spacer and the collector layer to form a SiGe/Si layer; forming a base electrode on the SiGe/Si layer; exposing a portion of the first oxidation film and forming a third oxidation film; exposing a surface of the SiGe/Si layer and forming a oxidation spacer on sides of an etched portion, then self-aligning the emitter and the emitter electrode; and performing a metal wiring process.
Abstract:
Disclosed is a method of fabricating a metal semiconductor field effect transistor, comprising the steps for, forming the channel using an ion-implantation, sequentially forming a first insulator layer at a first predetermined temperature and a second insulation layer at second predetermined temperature over the surface of the substrate, etching the first and second insulation layers using a gate pattern of a photo-resist pattern to expose the channel region as a mask, forming a refractory metal over the surface of the first and second insulation layer add the exposed channel region, etching the refractory metal, thereby dividing it into two parts of which one is formed on the channel region and the other is formed on the second insulation layer, selectively etching the first and second insulation layers to lift-off the refractory metal over the first and second insulation layers, thereby forming a gate of a T-shape on the channel region, ion implanting Si into a substrate using the gate and a channel pattern of a photo-resist film to form a self-aligned high concentration ion implantation region, forming a third insulation layer for preventing As of evaporation, carrying out a rapid thermal annealing for activation, removing the third insulation layer; and forming an ohmic electrode using a lift-off process.
Abstract:
The present invention relates to a bias stabilization circuit, specifically to a bias stabilization circuit for minimizing the current variations of amplification transistors caused by variations of device parameters which occur during the manufacturing of high-frequency integrated circuits using field-effect transistors, and caused by variations of supply voltage and temperature. In the present invention, the above problem is solved by configuring a level shifter circuit between the drain node and the gate node of the reference voltage generation transistor. Further, by using a constant current source utilizing a depletion transistor and series feedback resistors as a reference current, this circuit becomes stable against the variations of the device parameters as well as the variations of the temperature and supply voltage.
Abstract:
The present invention relates to a gain control circuit for a low-noise amplifier. A gain control circuit of a 2-stage low-noise amplifier comprising an input stage noise matching circuit, an intermediate impedance matching circuit, a gain control circuit, and an output stage impedance matching circuit, said gain control circuit including: a feedback circuit connected to a transistor of second stage of the 2-stage low-noise amplifier, said feedback circuit detecting the amplified signal through the first stage and the second stage, and feeding the signal back through a switch circuit; and an attenuation circuit for compensating the harmonics of the input signal.
Abstract:
The present invention relates to an equivalent circuit of a package ground terminal paddle which is used to mount a microwave integrated circuit, and more particularly, to an approximate equivalent circuit of the package ground terminal paddle by which the expressions of parasitic components can be easily expanded according to the number of gold wires that are down-bonded to the paddle, by introducing an equivalent circuit structure which takes the impedance component output from each terminal as one common impedance component and grounds the common impedance.
Abstract:
The invention relates to a method for manufacturing a super self-aligned heterojunction bipolar transistor which is capable of miniaturizing an element, simplifying the process step thereof by employing a selective collector epitaxial growth process without using a trench for isolating between elements. According to the invention, isolation between elements is derived by using a mask defining an emitter region and a second spacer. The base layer has multi-layer structure being made of a Si, an undoped SiGe, a SiGe doped a p-type impurity in-situ and Si. Also, the selective epitaxial growth for a base is not required. Thus, it can be less prone to a flow of leakage current or an emitter-base-collector short effect.
Abstract:
The present invention relates to a gain controlled amplifier, and more particularly, to a gain controlled amplifier using active feedback and variable resistance. It is an object of the present invention to provide a gain controlled amplifier minimizing the gain and the degradation of power characteristics generated when adjusting gain in a variable gain amplifier which receives signals having different power levels, amplifies them in accordance with each power level and outputs output signals in a constant power level. In order to achieve the above object, a gain controlled amplifier in accordance with the present invention comprises an amplifier and an active feedback means for negative feedbacking the output of the amplifier to the input of the amplifier, and further has a feedback amount controller inputting the controlled feedback signal to the amplifier by controlling the feedback amount of said active feedback means.
Abstract:
Disclosed is a micromirror for a hybrid optoelectronic integrated circuit, a method for manufacturing the same, a micromirror-photodetector assembly and an assembly of hybrid optoelectronic integrated circuit for receiving light. The micromirror the present invention comprises a silicon substrate and at least one V-shaped groove formed in the silicon substrate and the V-shaped groove has an inclined surface reflecting light emitted from an optical waveguide to a photodetector. The alignment of the photodetector and the optical fibers is achieved without an additional attachment equipment, by inserting the optical fibers into the V-groove.