A method for forming a power semiconductor device is provided. The method includes providing a substrate having a first surface and a second surface; and forming a plurality of trenches in the second surface of the substrate. The method also includes forming a semiconductor pillar in each of the plurality of trenches, wherein the semiconductor pillars and the substrate form a plurality of super junctions of the power semiconductor device for increasing the breakdown voltage of the power semiconductor device and reducing the on-stage voltage of the power semiconductor device; and forming a gate structure on the first surface of the substrate. Further, the method includes forming a plurality of well regions in the first surface of the substrate around the gate structure; and forming a source region in each of the plurality of well regions around the gate structure.

In one embodiment, a semiconductor device comprises a bulk semiconductor substrate that includes a first conductivity type floating buried doped region bounded above by a second conductivity type doped region and bounded below by another second conductivity semiconductor region. Dielectric isolation regions extend through the second conductivity doped region and the first conductivity floating buried doped region into the semiconductor region. Functional devices are disposed within the second conductivity type doped region. The first conductivity type floating buried doped region is configured as a self-biased region that laterally extends between adjacent dielectric isolation regions.

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.

An insulated gate bipolar transistor includes: a drift layer having a semiconductor substrate with N-type conductivity; a collector layer having P-type conductivity at a surface layer of the semiconductor substrate at a back surface side; and a field stop layer between the drift layer and the collector layer that has a higher impurity concentration than the drift layer. In a thickness direction of the semiconductor substrate, a lifetime control layer is arranged with a predetermined half value width by helium ion implantation; and the field stop layer is arranged with a predetermined half value width by hydrogen ion implantation. Further, a half value width region of the lifetime control layer and a half value width region of the field stop layer overlap each other.

Complementary high-voltage bipolar transistors in silicon-on-insulator (SOl) integrated circuits is disclosed. In one disclosed embodiment, a collector region is formed in an epitaxial silicon layer disposed over a buried insulator layer. A base region and an emitter are disposed over the collector region. An n-type region is formed under the buried insulator layer (BOX) by implanting donor impurity through the active region of substrate and BOX into a p-substrate. Later in the process flow this n-type region is connected from the top by doped poly-silicon plug and is biased at Vcc. In this case it will deplete lateral portion of PNP collector region and hence, will increase its BV.

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.

An LDMOS device in FinFET technology is disclosed. In one aspect, the device includes a first region substantially surrounded by a second region of different polarity. The device further includes a first fin in the first region, extending into the second region, the first fin including a doped source region connected with a first local interconnect. The device further includes a second fin in the second region, including a doped drain region connected with a second local interconnect. The device further includes a third fin parallel with the first and second fins including a doped drain region connected with the second local interconnect. The device further includes a gate over the first fin at the border between the first and second regions. A first current path runs over the first and second fins. A second current path runs over and perpendicular to the first fin towards the third fin.

Some embodiments of the present disclosure relate to a method to increase breakdown voltage of a power device. A power device is formed on a silicon-on-insulator (SOI) wafer made up of a device wafer, a handle wafer, and an intermediate oxide layer. A recess is formed in a lower surface of the handle wafer to define a recessed region of the handle wafer. The recessed region of the handle wafer has a first handle wafer thickness, which is greater than zero. An un-recessed region of the handle wafer has a second handle wafer thickness, which is greater than the first handle wafer thickness. The first handle wafer thickness of the recessed region provides a breakdown voltage improvement for the power device.

A semiconductor device of trench gate type is provided that has achieved both large on-current and high off-state breakdown voltage. Around trench T and between it and electric field relaxation p-layer 16, low resistance n-layer 17 is provided. Low resistance n-layer 17 is formed deeper than trench T, and shallower than electric field relaxation p-layer 16, being connected to n.sup.-layer (drift layer) 12 just thereunder, and thus low resistance n-layer 17 and n.sup.-layer 12 are integrated to form a drift layer. Although low resistance n-layer 17 is n-type as is n.sup.-layer 12, donor concentration thereof is set higher than that of n.sup.-layer 12, thereby low resistance n-layer 17 having a resistivity lower than that of n.sup.-layer 12. This low resistance n-layer 17 is provided in on-current path (between electric field relaxation p-layer 16 and trench T), whereby low resistance n-layer 17 can lower the resistance to on-current.

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.