In a trench gate type power MOSFET having a super-junction structure, both improvement of a breakdown voltage of a device and reduction of on-resistance are achieved. The trench gate and a column region are arranged so as to be substantially orthogonal to each other in a plan view, and a base region (channel forming region) and the column region are arranged separately in a cross-sectional view.

There is provided a semiconductor device including: a semiconductor layer including a main surface; a plurality of trenches including a plurality of first trench portions and a plurality of second trench portions, respectively; an insulating layer formed in an inner wall of each of the second trench portions; a first electrode buried in each of the second trench portions with the insulating layer interposed between the first electrode and each of the second trench portions; a plurality of insulators buried in the first trench portions so as to cover the first electrode; a contact hole formed at a region between the plurality of first trench portions in the semiconductor layer so as to expose the plurality of insulators; and a second electrode buried in the contact hole.

A super junction structure having a high aspect ratio is formed. An epitaxial layer is dividedly formed in layers using the trench fill process, and when each of the layers has been formed, trenches are formed in that layer. For example, when a first epitaxial layer has been formed, first trenches are formed in the epitaxial layer. Subsequently, when a second epitaxial layer has been formed, second trenches are formed in the epitaxial layer. Subsequently, when a third epitaxial layer has been formed, third trenches are formed in the third epitaxial layer.

A MOS transistor, in particular a vertical channel transistor, includes a semiconductor body housing a body region, a source region, a drain electrode and gate electrodes. The gate electrodes extend in corresponding recesses which are symmetrical with respect to an axis of symmetry of the semiconductor body. The transistor also has spacers which are also symmetrical with respect to the axis of symmetry. A source electrode extends in electrical contact with the source region at a surface portion of the semiconductor body surrounded by the spacers and is in particular adjacent to the spacers. During manufacture the spacers are used to form in an auto-aligning way the source electrode which is symmetrical with respect to the axis of symmetry and equidistant from the gate electrodes.

Semiconductor devices and methods of forming the devices are provided. Semiconductor devices include a semiconductor layer structure comprising a trench in an upper surface thereof, a dielectric layer in a lower portion of the trench, and a gate electrode in the trench and on the dielectric layer opposite the semiconductor layer structure. The trench may include rounded upper corner and a rounded lower corner. A center portion of a top surface of the dielectric layer may be curved, and the dielectric layer may be on opposed sidewalls of the trench. The dielectric layer may include a bottom dielectric layer on a bottom surface of the trench and on lower portions of the sidewalls of the trench and a gate dielectric layer on upper portions of the sidewalls of the trench and on the bottom dielectric layer.

A wide band gap semiconductor device includes a semiconductor layer, a trench formed in the semiconductor layer, first, second, and third regions having particular conductivity types and defining sides of the trench, and a first electrode embedded inside an insulating film in the trench. The second region integrally includes a first portion arranged closer to a first surface of the semiconductor layer than to a bottom surface of the trench, and a second portion projecting from the first portion toward a second surface of the semiconductor layer to a depth below a bottom surface of the trench. The second portion of the second region defines a boundary surface with the third region, the boundary region being at an incline with respect to the first surface of the semiconductor layer.

A semiconductor device includes a gate structure extending from a first surface of a semiconductor portion into a mesa section between neighboring field electrode structures and an alignment layer formed on the first surface. The alignment layer includes mask pits formed in the alignment layer in a vertical projection of the field electrode structures. Sidewalls of the mask pits have a smaller tilt angle with respect to the first surface than sidewalls of the field electrode structures. The gate structure is in the vertical projection of a gap between neighboring mask pits.

Disclosed is a manufacturing method of a trench-type power device. The manufacturing method comprises: forming a drift region; forming a first trench and a second trench in the drift region; forming a gate stack in the first trench; forming a doped region and a well region of P type in the drift region by performing first ion implantation; forming a source region of N type in the well region by performing second ion implantation. The well region in which a dopant concentration gradually decreases with depth is formed by the first ion implantation, an upper part of the well region is inverted by the second ion implantation to form the source region. The doped region and well region can be formed by self-alignment in a common ion implantation step, improving power device performance, reducing numbers of process steps of ion implantation and masks, reducing manufacturing cost.

A MOSFET includes a semiconductor body having a first side, a drift region, a body region forming a first pn-junction with the drift region, a source region forming a second pn-junction with the body region, in a vertical cross-section, a dielectric structure on the first side and having an upper side; a first gate electrode, a second gate electrode, a contact trench between the first and second gate electrodes, extending through the dielectric structure to the source region, in a horizontal direction a width of the contact trench has, in a first plane, a first value, and, in a second plane, a second value which is at most about 2.5 times the first value, and a first contact structure arranged on the dielectric structure having a through contact portion arranged in the contact trench, and in Ohmic contact with the source region.

A semiconductor device has an impurity region covering a bottom of a gate trench and a column region. A bottom of the column region is deeper than a bottom of the gate trench. The impurity region is arranged between the gate trench and the column region. This structure can improve the characteristics of the semiconductor device.