Abstract: Provided are an optical network terminal (ONT) and a method for the ONT to detect an optical transmission error. The ONT is connected with an optical line termination (OLT) and constituting a passive optical network (PON), and includes an optical transmitter configured to transmit an optical signal to the OLT, an error detector configured to detect an error of the optical transmitter; and a controller configured to transmit an error message to the OLT through the optical transmitter when the error detector detects an error of the optical transmitter.

Abstract: Integrated circuit devices are provided including a first single-crystalline layer and an insulating layer pattern on the first single-crystalline layer. The insulating layer pattern has an opening therein that partially exposes the first single-crystalline layer. A seed layer is in the opening. A second single-crystalline layer is on the insulating layer pattern and the seed layer. The second single-crystalline layer has a crystalline structure substantially the same as that of the seed layer. A transcription-preventing pattern is on the second single-crystalline layer and a third single-crystalline layer on the transcription-preventing pattern and the second single-crystalline layer. The transcription-preventing pattern is configured to limit transcription of defective portions in the second single-crystalline layer into the third single-crystalline layer.

Abstract: Integrated circuit devices are provided including a first single-crystalline layer and an insulating layer pattern on the first single-crystalline layer. The insulating layer pattern has an opening therein that partially exposes the first single-crystalline layer. A seed layer is in the opening. A second single-crystalline layer is on the insulating layer pattern and the seed layer. The second single-crystalline layer has a crystalline structure substantially the same as that of the seed layer. A transcription-preventing pattern is on the second single-crystalline layer and a third single-crystalline layer on the transcription-preventing pattern and the second single-crystalline layer. The transcription-preventing pattern is configured to limit transcription of defective portions in the second single-crystalline layer into the third single-crystalline layer.

Abstract: Embodiments of the invention provide a semiconductor integrated circuit device and a method for fabricating the device. The semiconductor device includes a semiconductor substrate having a cell region and a peripheral region, a cell active region formed in the cell region, and a peripheral active region formed in the peripheral region, wherein the cell active region and the peripheral active region are defined by isolation regions. The semiconductor device further includes a first gate stack formed on the cell active region, a second gate stack formed on the peripheral active region, a cell epitaxial layer formed on an exposed portion of the cell active region, and a peripheral epitaxial layer formed on an exposed portion of the peripheral active region, wherein the height of the peripheral epitaxial layer is greater than the height of the cell epitaxial layer.

Abstract: Embodiments of the invention provide a semiconductor integrated circuit device and a method for fabricating the device. The semiconductor device includes a semiconductor substrate having a cell region and a peripheral region, a cell active region formed in the cell region, and a peripheral active region formed in the peripheral region, wherein the cell active region and the peripheral active region are defined by isolation regions. The semiconductor device further includes a first gate stack formed on the cell active region, a second gate stack formed on the peripheral active region, a cell epitaxial layer formed on an exposed portion of the cell active region, and a peripheral epitaxial layer formed on an exposed portion of the peripheral active region, wherein the height of the peripheral epitaxial layer is greater than the height of the cell epitaxial layer.

Abstract: Metal-oxide-semiconductor (MOS) transistors having elevated source/drain regions and methods of fabricating the same are provided. The MOS transistors may include a gate pattern formed to cross over a predetermined region of a substrate. Recessed regions are provided in the substrate adjacent to the gate pattern. Epitaxial layers are provided on bottom surfaces of the recessed regions. High concentration impurity regions are provided in the epitaxial layers. The recessed regions may be formed using a chemical dry etching techniques.

Abstract: Methods of fabricating metal-oxide-semiconductor (MOS) transistors having elevated source/drain regions are provided. The MOS transistors formed by these methods may include a gate pattern formed to cross over a predetermined region of a substrate. Recessed regions are provided in the substrate adjacent to the gate pattern. Epitaxial layers are provided on bottom surfaces of the recessed regions. High concentration impurity regions are provided in the epitaxial layers. The recessed regions may be formed using a chemical dry etching techniques.

Abstract: A semiconductor device can include a first gate electrode including a gate insulating pattern, a gate conductive pattern and a capping pattern that are sequentially stacked on a semiconductor substrate, and a first spacer of a low dielectric constant disposed on a lower sidewall of the first gate electrode. A second spacer of a high dielectric constant, that is greater than the low dielectric constant, is disposed on an upper sidewall of the first gate electrode above the first spacer.

Abstract: A field effect transistor includes a vertical fin-shaped semiconductor active region having an upper surface and a pair of opposing sidewalls on a substrate, and an insulated gate electrode on the upper surface and opposing sidewalls of the fin-shaped active region. The insulated gate electrode includes a capping gate insulation layer having a thickness sufficient to preclude formation of an inversion-layer channel along the upper surface of the fin-shaped active region when the transistor is disposed in a forward on-state mode of operation. Related fabrication methods are also discussed.

Abstract: Provided are a DRAM semiconductor device and a method for fabricating the DRAM semiconductor device. The method provides forming a silicon epitaxial layer on a source/drain region of a cell region and a peripheral circuit region using selective epitaxial growth (SEG), thereby forming a raised active region. In addition, in the DRAM semiconductor device, a metal silicide layer and a metal pad are formed on the silicon epitaxial layer in the source/drain region of the cell region. By doing this, the DRAM device is capable of forming a source/drain region as a shallow junction region, reducing the occurrence of leakage current and lowering the contact resistance with the source/drain region.

Abstract: A method of fabricating a semiconductor device includes forming a buffer pattern on a substrate, the buffer pattern including germanium, recrystallizing the buffer pattern to form a strained relaxation buffer pattern, and forming a tensile silicon cap on the strained relaxation buffer pattern, the cap being under tensile strain.

Abstract: Disclosed is a semiconductor fin construction useful in FinFET devices that incorporates an upper region and a lower region with wherein the upper region is formed with substantially vertical sidewalls and the lower region is formed with inclined sidewalls to produce a wider base portion. The disclosed semiconductor fin construction will also typically include a horizontal step region at the interface between the upper region and the lower region. Also disclosed are a series of methods of manufacturing semiconductor devices incorporating semiconductor fins having this dual construction and incorporating various combinations of insulating materials such as silicon dioxide and/or silicon nitride for forming shallow trench isolation (STI) structures between adjacent semiconductor fins.

Abstract: Fin-Field Effect Transistors (Fin-FETs) are provided. A fin is provided on an integrated circuit substrate. The fin defines a trench on the integrated circuit substrate. A first insulation layer is provided in the trench such that a surface of the first insulation layer is recessed beneath a surface of the fin exposing sidewalls of the fin. A protection layer is provided on the first insulation layer and a second insulation layer is provided on the protection layer in the trench such that protection layer is between the second insulation layer and the sidewalls of the fin.

Abstract: A semiconductor memory device may include a semiconductor substrate with an active region extending in a first direction parallel with respect to a surface of the semiconductor substrate. A pillar may extend from the active region in a direction perpendicular with respect to the surface of the semiconductor substrate with the pillar including a channel region on a sidewall thereof. A gate insulating layer may surround a sidewall of the pillar, and a word line may extend in a second direction parallel with respect to the surface of the semiconductor substrate. Moreover, the first and second directions may be different, and the word line may surround the sidewall of the pillar so that the gate insulating layer is between the word line and the pillar. A contact plug may be electrically connected to the active region and spaced apart from the word line, and a bit line may be electrically connected to the active region through the contact plug with the plurality of bit lines extending in the first direction.

Abstract: Integrated circuit field effect transistors include an integrated circuit substrate and a fin that projects away from the integrated circuit substrate, extends along the integrated circuit substrate, and includes a top that is remote from the integrated circuit substrate. A channel region is provided in the fin that is doped a conductivity type and has a higher doping concentration of the conductivity type adjacent the top than remote from the top. A source region and a drain region are provided in the fin on opposite sides of the channel region, and an insulated gate electrode extends across the fin adjacent the channel region. Related fabrication methods also are described.

Abstract: Semiconductor devices have gate structures on a semiconductor substrate with first spacers on sidewalls of the respective gate structures. First contact pads are positioned between the gate structures and have heights lower than the heights of the gate structures. Second spacers are disposed on sidewalls of the first spacers and on exposed sidewalls of the first contact pads. Second contact pads are disposed on the first contact pads.

Abstract: A method of forming a semiconductor device may include forming a fin structure extending from a substrate. The fin structure may include first and second source/drain regions and a channel region therebetween, and the first and second source/drain regions may extend a greater distance from the substrate than the channel region. A gate insulating layer may be formed on the channel region, and a gate electrode may be formed on the gate insulating layer so that the gate insulating layer is between the gate electrode and the channel region. Related devices are also discussed.

Abstract: Embodiments of the present invention include heterogeneous substrates, integrated circuits formed on such heterogeneous substrates. The heterogeneous substrates according to certain embodiments of the present invention include a first Group IV semiconductor layer (e.g., silicon), a second Group IV pattern (e.g., a silicon-germanium pattern) that includes a plurality of individual elements on the first Group IV semiconductor layer, and a third Group IV semiconductor layer (e.g., a silicon epitaxial layer) on the second Group IV pattern and on a plurality of exposed portions of the first Group IV semiconductor layer. The second Group IV pattern may be removed in embodiments of the present invention. In these and other embodiments of the present invention, the third Group IV semiconductor layer may be planarized.

Abstract: Embodiments of the present invention include heterogeneous substrates, integrated circuits formed on such heterogeneous substrates, and methods of forming such substrates and integrated circuits. The heterogeneous substrates according to certain embodiments of the present invention include a first Group IV semiconductor layer (e.g., silicon), a second Group IV pattern (e.g., a silicon-germanium pattern) that includes a plurality of individual elements on the first Group IV semiconductor layer, and a third Group IV semiconductor layer (e.g., a silicon epitaxial layer) on the second Group IV pattern and on a plurality of exposed portions of the first Group IV semiconductor layer. The second Group IV pattern may be removed in embodiments of the present invention. In these and other embodiments of the present invention, the third Group IV semiconductor layer may be planarized.

Abstract: A method of forming a fin field effect transistor on a semiconductor substrate includes forming an active region in the substrate, forming an epitaxial layer on the active region, and removing a portion of the epitaxial layer to form a vertical fin on the active region. The fin has a width that is narrower than a width of the active region. Removing a portion of the epitaxial layer may include oxidizing a surface of the epitaxial layer and then removing the oxidized surface of the epitaxial layer to decrease the width of the fin. The epitaxial layer may be doped in situ before removing a portion of the epitaxial layer. The method further includes forming a conductive layer on a top surface and on sidewalls of the fin. Related transistors are also discussed.