A semiconductor device includes a substrate having an upper surface layer of a second conduction type formed at an upper surface side, a drift layer of a first conduction type formed under the upper surface layer, a buffer layer of the first conduction type formed under the drift layer, and a lower surface layer of the second conduction type formed under the buffer layer, the buffer layer includes a plurality of upper buffer layers provided apart from each other, and a plurality of lower buffer layers provided apart from each other between the plurality of upper buffer layers and the lower surface layer, wherein the plurality of upper buffer layers are formed so that average impurity concentrations in first sections each extending from the upper end of one of the upper buffer layers to the next lower buffer layer are unified as a first concentration.

Provided are a weighting device that may be driven at a low voltage and is capable of embodying multi-level weights, a neural network, and a method of operating the weighting device. The weighting device includes a switching layer that may switch between a high resistance state and a low resistance state based on a voltage applied thereto and a charge trap material layer that traps or discharges charges according to a resistance state of the switching layer. The weighting device may be used for controlling a weight in a neural network.

Provided are a low-cost semiconductor device manufacturing method and a semiconductor device made using the method. The method includes forming multiple body regions in a semiconductor substrate, forming multiple gate insulating layers and multiple gate electrodes in the body region; implementing a blanket ion implantation in an entire surface of the substrate to form a low concentration doping region (LDD region) in the body region without a mask, forming a spacer at a side wall of the gate electrode, and implementing a high concentration ion implantation to form a high concentration source region and a high concentration drain region around the LDD region. According to the examples, devices have favorable electrical characteristics and at the same time, manufacturing costs are reduced. Since, when forming high concentration source region and drain regions, tilt and rotation co-implants are applied, an LDD masking step is potentially omitted.

The present examples relate to a semiconductor device used in an electric device or high voltage device. The present examples improve R.sub.sp by minimizing drift region resistance by satisfying breakdown voltage by improving the structure of a drift region through which current flows in a semiconductor device to provide optimal results. Moreover, a high frequency application achieves useful results by reducing a gate charge Q.sub.g for an identical device pitch to that of an alternative technology.

A method for doping fins includes depositing a first dopant layer at a base of fins formed in a substrate, depositing a dielectric layer on the first dopant layer and etching the dielectric layer and the first dopant layer in a first region to expose the substrate and the fins. A second dopant layer is conformally deposited over the fins and the substrate in the first region. The second dopant layer is recessed to a height on the fins in the first region. An anneal is performed to drive dopants into the fins from the first dopant layer in a second region and from the second dopant layer in the first region to concurrently form punch through stoppers in the fins and wells in the substrate.

A method for doping fins includes depositing a first dopant layer at a base of fins formed in a substrate, depositing a dielectric layer on the first dopant layer and etching the dielectric layer and the first dopant layer in a first region to expose the substrate and the fins. A second dopant layer is conformally deposited over the fins and the substrate in the first region. The second dopant layer is recessed to a height on the fins in the first region. An anneal is performed to drive dopants into the fins from the first dopant layer in a second region and from the second dopant layer in the first region to concurrently form punch through stoppers in the fins and wells in the substrate.

A semiconductor device includes a transistor. The transistor includes a source region and a drain region disposed adjacent to a first main surface of a semiconductor substrate, a first gate electrode and a second gate electrode, the first gate electrode being disconnected from the second gate electrode. The transistor further includes a body region. The first gate electrode is adjacent to a first portion of the body region and the second gate electrode is adjacent to a second portion of the body region. The transistor further includes first trenches patterning the first portion of the body region into a first ridge, and second trenches patterning the second portion of the body region into a second ridge. The first gate electrode is arranged in at least one of first trenches, and the second gate electrode is arranged in at least one of the second trenches.

A semiconductor device includes a substrate, and a stacked portion over the substrate, the stacked structure including a first nitride semiconductor layer containing aluminum, a second nitride semiconductor layer containing carbon, and a third nitride semiconductor layer whose carbon concentration is lower than carbon concentration of the second nitride semiconductor layer. A fourth nitride semiconductor layer whose carbon concentration is lower than carbon concentration of the second nitride semiconductor layer and whose thickness is greater than the thickness of each of the first to third nitride semiconductor layers is provided on an upper surface of the stacked portion. A fifth nitride semiconductor layer containing aluminum is provided on an upper surface of the fourth nitride semiconductor layer. A first electrode is provided on an upper surface of the fifth nitride semiconductor layer.

A semiconductor device and a fabrication method thereof are provided. The semiconductor device includes a P type well region and an N type well region formed in a substrate, a gate insulating layer having a non-uniform thickness and formed on the P type well region and the N type well region, a gate electrode formed on the gate insulating layer, a P type well pick-up region formed in the P type well region, and a field relief oxide layer formed in the N type well region between the gate electrode and the drain region.

There is provided a semiconductor device having LDMOS transistors embedded in a semiconductor substrate to boost source-drain breakdown voltage, with arrangements to prevent fluctuations of element characteristics caused by electric field concentration so that the reliability of the semiconductor device is improved. A trench is formed over the upper surface of a separation insulating film of each LDMOS transistor, the trench having a gate electrode partially embedded therein. This structure prevents electric field concentration in the semiconductor substrate near the source-side edge of the separation insulating film.