An Enhanced Planar MOS cell based on a simple and self-aligned process provides a structure where the lateral distance between the edge of the gate electrode opening and the end of the P-well region is less than 70% from the vertical distance between the surface of the substrate and the depth of the P-well region. Usually, for previous designs, this ratio was 70-80% or more. A spacer can be introduced at the edge of the polysilicon gate electrode openings after the diffusion of an enhancement layer. Using the spacer, a P-type implant is made, resulting in a shorter lateral MOS channel, while the vertical depth of the P-well remains unchanged. The design results in much lower on-state losses without affecting the voltage blocking capability of the device. This design offers advantages both in terms of performance and processability and can be applied to both IGBTs and MOSFETs.

A transistor device includes at least one transistor cell, having, in a semiconductor body, a source region of a first doping type in a body region of a second doping type, a drain region, and a drift region of the first doping type adjoining the body region and arranged between the body region and the drain region. A low-resistance region of the second doping type in the body region adjoins the source region. A gate electrode dielectrically insulated from the source and body regions by a gate dielectric is arranged above a first surface of the semiconductor body. A length of an overlap between the source region and the gate electrode is larger than 70 nanometers. A doping profile of the low-resistance region along a line that is vertical to the first surface and goes through an edge of the gate electrode has a maximum of higher than 1E19 cm.sup.3.

Trench MOSFET with self-aligned body contact with spacer. In accordance with an embodiment of the present invention, a plurality of gate trenches are formed into a semiconductor substrate. A body contact trench is formed into the semiconductor substrate in a mesa between the gate trenches. Spacers are deposited on sidewalls of the body contact trench. An ohmic body contact is implanted into the semiconductor substrate through the body contact trench utilizing the spacers to self-align the implant. A body contact trench extension may be etched into the semiconductor substrate through the body contact trench utilizing the spacers to self-align the etch, prior to the implant.

Semiconductor device structures comprising a spacer feature having multiple spacer layers are provided. In one example, a semiconductor device includes an active area on a substrate, the active area comprising a source/drain region, a gate structure over the active area, the source/drain region being proximate the gate structure, a spacer feature having a first portion along a sidewall of the gate structure and having a second portion along the source/drain region, wherein the first portion of the spacer feature comprises a bulk spacer layer along the sidewall of the gate structure, wherein the second portion of the spacer feature comprises the bulk spacer layer and a treated seal spacer layer, the treated seal spacer layer being disposed along the source/drain region and between the bulk spacer layer and the source/drain region, and a contact etching stop layer on the spacer feature.

First trenches extend from a process surface into a semiconductor layer. An alignment layer with mask pits in a with respect to the process surface vertical projection of the first trenches is formed on the process surface. Sidewalls of the mask pits have a smaller tilt angle with respect to the process surface than sidewalls of the first trenches. The mask pits are filled with an auxiliary material. A gate trench for a gate structure is formed in a mesa section of the semiconductor layer between the first trenches, wherein the auxiliary material is used as an etch mask.

Trench MOSFET with self-aligned body contact with spacer. In accordance with an embodiment of the present invention, a semiconductor device includes a semiconductor substrate, and at least two gate trenches formed in the semiconductor substrate. Each of the trenches comprises a gate electrode. The semiconductor device also includes a body contact trench formed in the semiconductor substrate between the gate trenches. The body contact trench has a lower width at the bottom of the body contact trench and an ohmic body contact implant beneath the body contact trench. The horizontal extent of the ohmic body contact implant is not greater than the lower width of the body contact trench.

A method for manufacturing a MOSFET semiconductor device includes providing a wafer including a semiconductor body having a first side, a first semiconductor region adjacent to the first side, a second semiconductor region adjacent to the first side and forming a first pn-junction with the first semiconductor region, and a third semiconductor region adjacent to the first side and forming a second pn-junction with the second semiconductor region, a first dielectric layer arranged on the first side, a gate electrode embedded in the first dielectric layer, and a second dielectric layer arranged on the first dielectric layer. Next to the gate electrode, a trench is formed through the first dielectric layer and the second dielectric layer. At a side wall of the trench, a dielectric spacer is formed. The trench is extended into the semiconductor body to form a contact trench.

A method of forming a semiconductor device includes forming a P-type heavily doped region in a substrate. A sacrificial layer is formed on the substrate and covers the P-type heavily doped region. The sacrificial layer is patterned, so that sidewalls of the sacrificial layer are above the substrate inside the P-type heavily doped region. An N-type heavily doped region adjacent to the P-type heavily doped region is formed in the substrate by using the sacrificial layer as mask. A wet etching process is performed to retract the sidewalls of the sacrificial layer to the substrate inside the N-type heavily doped region. A P-type lightly doped region is formed in the substrate by using the sacrificial layer as mask. The P-type lightly doped region is adjacent to the N-type heavily doped region, and is in contact with bottoms of the P-type heavily doped region and the N-type heavily doped region.

An embodiment relates to a method comprising obtaining a SiC substrate comprising a N+ substrate and a N drift layer; depositing a first hard mask layer on the SiC substrate and patterning the first hard mask layer; performing a p-type implant to form a p-well region; depositing a second hard mask layer on top of the first hard mask layer; performing an etch back of at least the second hard mask layer to form a sidewall spacer; implanting N type ions to form a N+ source region that is self-aligned; and forming a MOSFET.

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.