An insulating film and another insulating film are formed over a semiconductor substrate in that order to cover first, second, and third gate electrodes. The another insulating film is etched back to form sidewall spacers over side surfaces of the insulating film. Then, the sidewall spacers over the side surfaces of the insulating films corresponding to the sidewalls of the first and second gate electrodes are removed to leave the sidewall spacers over the side surfaces of the insulating film corresponding to the sidewalls of the third gate electrode. Then, the sidewall spacers and the insulating films are etched back, so that the sidewall spacers are formed of the insulating film over the sidewalls of the first, second, and third gate electrodes.

A layered semiconductor includes a base layer including a substrate and a buffer layer, and a drift layer which is disposed on the base layer and is made of GaN and whose conductivity type is an n-type. The drift layer has an average n-type impurity concentration of 1.510.sup.16 cm.sup.3 or less in a radial direction of the substrate, and the difference between the maximum n-type impurity concentration and the minimum n-type impurity concentration is 1.510.sup.15 cm.sup.3 or less.

When hydrogen penetrates in to the semiconductor device, a gate voltage threshold of a gate structure (Vth) is shifted.

Penetrating of hydrogen into the semiconductor device from the edge termination structure section which is positioned at an end portion of the semiconductor device is prevented.

To provide a semiconductor device comprising a semiconductor substrate in which an active region and an edge termination structure section which is provided around the active region are provided, a first lower insulating film which is provided in the edge termination structure section on the semiconductor substrate, and a first protective film which is provided on the first lower insulating film, and is electrically insulated from the semiconductor substrate, and occludes hydrogen.

In a semiconductor device having a silicon carbide device, a technique capable of suppressing variation in a breakdown voltage and achieving reduction in an area of a termination structure is provided. In order to solve the above-described problem, in the present invention, in a semiconductor device having a silicon carbide device, a p-type first region and a p-type second region provided to be closer to an outer peripheral side than the first region are provided in a junction termination portion, a first concentration gradient is provided in the first region, and a second concentration gradient larger than the first concentration gradient is provided in the second region.

A super-junction semiconductor device is provided. The super-junction semiconductor device includes a substrate, a drift layer, a field insulator, a floating electrode layer, an isolation layer, and at least one transistor structure. The drift layer includes a plurality of n-type and p-type pillars alternately arranged in parallel to form a super-junction structure. An active region, a termination region and a transition region located therebetween are defined in the drift layer. The field insulator disposed on a surface of the drift layer covers the termination region and a portion of the transition region. The floating electrode layer disposed on the field insulator partially overlaps with the termination region. The transistor structure includes a source conductive layer extending from the active region to the transition region and superimposed on a portion of the floating electrode layer. The source conductive layer is isolated from the floating electrode layer by the isolation layer.

A semiconductor device includes a transistor cell area with active transistor cells including source zones electrically connected to a first load electrode. The source zones have a first conductivity type. An edge area surrounds the active transistor cell area and includes an edge construction that includes straight sections and a corner section connecting neighboring straight sections. A second dopant ratio between a mean concentration of dopants of a complementary second conductivity type and a mean concentration of dopants of the first conductivity type in the corner section exceeds a first dopant ratio between a mean concentration of dopants of the second conductivity type and a mean concentration of dopants of the first conductivity type in the straight sections by at least 0.2% in relation to the first dopant ratio.

Semiconductor devices are formed using a thin epitaxial layer (nanotube) formed on sidewalls of dielectric-filled trenches. In one embodiment, a method for forming a semiconductor device includes forming a first epitaxial layer on sidewalls of trenches and forming second epitaxial layer on the first epitaxial layer where charges in the doped regions along the sidewalls of the first and second trenches achieve charge balance in operation. In another embodiment, the semiconductor device includes a termination structure including an array of termination cells.

A die stack assembly includes first and second power semiconductor device dice. The first die has a P type peripheral edge separation structure that extends from the top planar semiconductor surface of the first die all the way to the bottom planar semiconductor surface of the die, and that is doped at least in part with aluminum. The backside of the first die is mounted to the backside of the second die. A metal feature that is not covered with passivation, and that can serve as a bonding pad, is disposed on part of the peripheral edge separation structure. A metal member (for example, a bond wire or metal clip) contacts the metal feature such that an electrical connection is established from the metal member, through the metal feature, through the peripheral edge separation structure of the first die, and to an electrode of the second die.

A super-junction semiconductor device includes a junction termination area at a first surface of a semiconductor body and at least partly surrounding an active cell area. An inner part of the junction termination area is arranged between an outer part of the junction termination area and the active cell area. A charge compensation device structure includes first regions of a first conductivity type and second regions of a second conductivity type disposed alternately along a first lateral direction. First surface areas correspond to a projection of the first regions onto the first surface, and second surface areas correspond to a projection of the second regions onto the first surface. The super-junction semiconductor device further includes at least one of a first junction termination extension structure and a second junction termination extension structure.

High voltage devices and methods for forming a high voltage device are disclosed. The method includes providing a substrate having top and bottom surfaces. The substrate is defined with a device region and a recessed region disposed within the device region. The recessed region includes a recessed surface disposed lower than the top surface of the substrate. A transistor is formed over the substrate. Forming the transistor includes forming a gate at least over the recessed surface and forming a source region adjacent to a first side of the gate below the recessed surface. Forming the transistor also includes forming a drain region displaced away from a second side of the gate. First and second device wells are formed in the substrate within the device region. The first device well encompasses the drain region and the second device well encompasses the source region.