Electronics and Telecommunications Research Institute

Hong Gu Ji

Jae Kyoung Mun

Hae Cheon Kim

Ho Kyun Ahn

Woo Jin Chang

Jong Won Lim

Dong Min Kang

Hokyun Ahn

Jong-Won Lim

Byoung-Gue Min

Sang-Heung Lee

Dong-Young Kim

Jongmin Lee

Kyu Jun Cho

Woojin Chang

Hea Cheon Kim

Hyun Kyu Yu

Hyung Sup Yoon

Seong-Il Kim

Jae Won Do

Sungjae Chang

Hyunwook Jung

Yoo Jin Jang

Min Jeong Shin

Eun Soo Nam

Hyung Seok Lee

Haecheon Kim

Heacheon Kim

Jeong Jin Kim

Jong Yul Park

Disclosed is a switch circuit for an ultra-high frequency band, which includes a transistor including a first terminal connected to an input stage, a second terminal connected to an output stage, and a gate terminal, an inductor connected to the transistor in parallel, between the input stage and the output stage, a variable gate driver to apply a gate input voltage to the gate terminal and, an input resistor connected between the variable gate driver and the gate terminal. The variable gate driver adjusts the gate input voltage to be in one of a first voltage level for turning on the transistor and a second voltage level for turning off the transistor. The second voltage level varies depending on a capacitance between the first terminal and the second terminal, when the transistor is in a turn-off state.

Switch circuit for ultra-high frequency band

Disclosed is a frequency mixer. The frequency mixer includes a first matching circuit that generates a matched local oscillator (LO) signal based on an LO signal, a non-linear circuit that generates a non-linear LO signal based on the matched LO signal, a second matching circuit that generates a matched radio frequency (RF) signal based on an RF signal, a mixing circuit that generates a mixed signal based on a mixing of the non-linear LO signal and the matched RF signal, a third matching circuit that generates an intermediate frequency (IF) signal based on the mixed signal, wherein the non-linear circuit includes a non-linear transistor, a bias transistor, and an internal matching circuit connected in series.

Frequency mixer including non-linear circuit

Provided is a semiconductor device including a substrate in which an insulation layer is disposed between a first semiconductor layer and a second semiconductor layer, a through-hole penetrating through the substrate, the through-hole having a first hole penetrating through the first semiconductor layer and a second hole penetrating through the insulation layer and the second semiconductor layer from a bottom surface of the first hole, an epi-layer disposed inside the through-hole, a drain electrode disposed inside the second hole and contacting one surface of the epi-layer, and a source electrode and a gate electrode which are disposed on the other surface of the epi-layer.

Semiconductor device having a drain electrode contacting an epi material inside a through-hole and method of manufacturing the same

Provided is a cascode circuit including first and second transistors connected between a drain terminal and a source terminal in cascode form, a level sifter configured to change a voltage level of a switching control signal applied to a gate terminal and provide the changed switching control signal to a gate of the first transistor, a buffer configured to delay the switching control signal and provide the delayed switching control signal to a gate of the second transistor, and a first resistor connected between the level shifter and the gate of the first transistor.

Cascode switch circuit including level shifter

Provided are a transistor of a semiconductor device and a method of fabricating the same. The transistor of a semiconductor device includes an epitaxial substrate having a buffer layer, a first silicon (Si) planar doped layer, a first conductive layer, a second Si planar doped layer having a different dopant concentration from the first Si planar doped layer, and a second conductive layer, which are sequentially formed on a semi-insulating substrate; a source electrode and a drain electrode formed on both sides of the second conductive layer to penetrate the first Si planar doped layer to a predetermined depth to form an ohmic contact; and a gate electrode formed on the second conductive layer between the source electrode and the drain electrode to form a contact with the second conductive layer, wherein the gate electrode, the source electrode and the drain electrode are electrically insulated by an insulating layer, and a predetermined part of an upper part of the gate electrode is formed to overlap at least one of the source electrode and the drain electrode. Therefore, a maximum voltage that can be applied to the switching device is increased due to increases of a gate turn-on voltage and a breakdown voltage, and decrease of a parallel conduction component. As a result of this improved power handling capability, high-power and low-distortion characteristics and high isolation can be expected from the switching device.

Transistor of semiconductor device and method of fabricating the same

Provided is a power amplifier including: a depletion mode high electron mobility transistor (D-mode HEMT) configured to amplify a signal inputted to a gate terminal and output the amplified signal through a drain terminal; an input matching circuit configured to serially ground the gate terminal; and a DC bias circuit connected between the drain terminal and a ground. Through the foregoing configuration, the HEMT may be biased only by a single DC bias circuit without any biasing means to provide a negative voltage. Also, superior matching characteristic may be provided in various operation frequency bands through a shunt inductor and a choke inductor.

Power amplifier having depletion mode high electron mobility transistor

Provided is a high-speed optical interconnection device. The high-speed optical interconnection device includes a first semiconductor chip, light emitters, optical detectors, and a second semiconductor chip, which are disposed on a silicon-on-insulator (SOI) substrate. The light emitters receive electrical signals from the first semiconductor chip to output optical signals. The optical detectors detect the optical signals to convert the optical signals into electrical signals. The second semiconductor chip receives the electrical signals converted by the optical detectors.

High-speed optical interconnection device

Provided are a semiconductor device with a T-gate electrode capable of improving stability and a high frequency characteristic of the semiconductor device by reducing source resistance, parasitic capacitance, and gate resistance and a method of fabricating the same. In the semiconductor device, in order to form source and drain electrodes and the T-gate electrode on a substrate, first and second protective layers constructed with silicon oxide layers or silicon nitride layers are formed on sides of a supporting part under a head part of the T-gate electrode, and the second protective layer constructed with a silicon oxide layer or silicon nitride layer is formed on sides of the source and drain electrodes. Accordingly, it is possible to protect an activated region of the semiconductor device and reduce gate-drain parasitic capacitance and gate-source parasitic capacitance.

Semiconductor device with T-gate electrode

A sub-harmonic mixer is provided, which includes: a mixer core having first and second transistors performing switching operations in response to a local oscillator (LO) signal and a radio frequency (RF) signal; a power source applying bias maximizing nonlinearity of a transistor included in the mixer core; an RF port applying an RF signal to the mixer core; an LO port applying an LO signal to the mixer core; and first and second phase delay circuits in which the RF signals applied to the first and second transistors have a 180-degree phase difference.

Sub-harmonic mixer

A field effect transistor having a T- or &#x393;-shaped fine gate electrode of which a head portion is wider than a foot portion, and a method for manufacturing the field effect transistor, are provided. A void is formed between the head portion of the gate electrode and a semiconductor substrate using an insulating layer having a multi-layer structure with different etch rates. Since parasitic capacitance between the gate electrode and the semiconductor substrate is reduced by the void, the head portion of the gate electrode can be made large so that gate resistance can be reduced. In addition, since the height of the gate electrode can be adjusted by adjusting the thickness of the insulating layer, device performance as well as process uniformity and repeatability can be improved.

Field effect transistor and method for manufacturing the same

Provided are a transistor of a semiconductor device and method of fabricating the same. The transistor includes: an epitaxy substrate disposed on a semi-insulating substrate and having a buffer layer, a first Si planar doping layer, a first conductive layer, a second Si planar doping layer, and a second conductive layer, which are sequentially stacked, the second Si planar doping layer having a doping concentration different from that of the first Si planar doping layer; a source electrode and a drain electrode diffusing into the first Si planar doping layer to a predetermined depth and disposed on both sides of the second conductive layer to form an ohmic contact; and a gate electrode disposed on the second conductive layer between the source and drain electrodes and being in contact with the second conductive layer. In this structure, both isolation and switching speed of the transistor can be increased. Also, the maximum voltage limit applied to the transistor is increased due to increases in gate turn-on voltage and threshold voltage and a reduction in parallel conduction element. As a result, the power handling capability of the transistor can be improved, thus improving a high-power low-distortion characteristic and an isolation characteristic.

Transistor or semiconductor device comprising ohmic contact in an epitaxy substrate

Provided is a power device having a connection structure compensating for a reactance component, in which transistors are arranged and connected to minimize deterioration of transistor properties caused by heat by compensating for a reactance component causing a phase difference due to transmission lines used for connecting a plurality of transistors in parallel such that the power device to be used for a high-frequency power amplifier outputs high power, and transmitting heat generated by high output power to a heat sink to be dissipated.

Power device having connection structure compensating for reactance component of transmission line

Provided is a method of fabricating a pseudomorphic high electron mobility transistor (PHEMT). The method includes the steps of: preparing a substrate including a channel layer and a capping layer that is the uppermost layer; forming a source and a drain on the capping layer; forming a first protective layer on the entire surface of the resultant structure and then patterning the first protective layer to expose a portion of the capping layer in a channel region; removing the exposed portion of the capping layer to form a first recess structure; forming a second protective layer on the entire surface of the resultant structure and then patterning the second protective layer to expose a portion of the substrate in the first recess structure so that a second recess structure is formed; forming a multilayered photoresist layer on the entire surface of the resultant structure and then patterning the multilayered photoresist layer to expose a portion of the substrate through the second recess structure and form a gate-shaped opening; and depositing a metal layer to fill the gate-shaped opening and then removing the multilayered photoresist layer to form a gate connected to the substrate through the second recess structure.

Growing community of inventors

Daejeon, South Korea

Hong Gu Ji