Methods of forming a semiconductor structure include providing a multi-layer substrate having an epitaxial base layer overlying a strained primary semiconductor layer above a buried oxide layer. Elements within the epitaxial base layer are used to alter a strain state in the primary semiconductor layer within a first region of the multi-layer substrate without altering a strain state in the primary semiconductor layer within a second region of the multi-layer substrate. A first plurality of transistor channel structures are formed that each comprise a portion of the primary semiconductor layer within the first region of the multi-layer substrate, and a second plurality of transistor channel structures are formed that each comprise a portion of the primary semiconductor layer within the second region of the multi-layer substrate. Semiconductor structures fabricated by such methods may include transistor channel structures having differing strain states.

Methods of forming a semiconductor structure include providing a multi-layer substrate having an epitaxial base layer overlying a strained primary semiconductor layer above a buried oxide layer. Elements within the epitaxial base layer are used to alter a strain state in the primary semiconductor layer within a first region of the multi-layer substrate without altering a strain state in the primary semiconductor layer within a second region of the multi-layer substrate. A first plurality of transistor channel structures are formed that each comprise a portion of the primary semiconductor layer within the first region of the multi-layer substrate, and a second plurality of transistor channel structures are formed that each comprise a portion of the primary semiconductor layer within the second region of the multi-layer substrate. Semiconductor structures fabricated by such methods may include transistor channel structures having differing strain states.

A solar cell includes: a semiconductor substrate which includes a first principal surface and a second principal surface; a first semiconductor layer of the first conductivity type disposed above the first principal surface; and a second semiconductor layer of a second conductivity type disposed below the second principal surface. The semiconductor substrate includes: a first impurity region of the first conductivity type; a second impurity region of the first conductivity type disposed between the first impurity region and the first semiconductor layer; and a third impurity region of the first conductivity type disposed between the first impurity region and the second semiconductor layer. A concentration of an impurity in the second impurity region is higher than a concentration of the impurity in the third impurity region, and the concentration of the impurity in the third impurity region is higher than a concentration of the impurity in the first impurity region.

A semiconductor device has transistor portions and diode portions. The transistor portions have a semiconductor substrate of a first conductivity type, a first semiconductor region of a second conductivity type, second semiconductor regions of the first conductivity type, gate insulating films, gate electrodes, a first semiconductor layer of the first conductivity type, a third semiconductor region of the second conductivity type, a first electrode, and a second electrode. The diode portions have the semiconductor substrate, the first semiconductor region, the first semiconductor layer, a fourth semiconductor region of the first conductivity type, the first electrode, and the second electrode. A first depth of the first semiconductor layer from the back surface of the semiconductor substrate in the transistor portions is greater than a second depth of the first semiconductor layer from the back surface of the semiconductor substrate in the diode portions.

A vertical field effect transistor (VFET) has a top source/drain (S/D) with a first region having a first area and a first capacitance and a second region having a second area and a second capacitance. A first top spacer on a gate cross section area. A second top spacer with a varying thickness is disposed the first top spacer. Both the first and second top spacers are between the top S/D and the gate cross section area. Due to the varying thickness of the second spacer with the smaller thickness closer to the fin, the separation distance between the larger, first area and the gate cross section area is greater than the separation distance between the smaller, second area and the gate cross section area. Therefore, the first capacitance is reduced because of the larger separation distance and the second capacitance is reduced because of the smaller second area. The smaller thickness of the second top spacer being closer to the fin allows dopants to diffuse a shorter distance when forming a junction between the top S/D and the channel of the VFET.

A vertical field effect transistor (VFET) has a top source/drain (S/D) with a first region having a first area and a first capacitance and a second region having a second area and a second capacitance. A first top spacer on a gate cross section area. A second top spacer with a varying thickness is disposed the first top spacer. Both the first and second top spacers are between the top S/D and the gate cross section area. Due to the varying thickness of the second spacer with the smaller thickness closer to the fin, the separation distance between the larger, first area and the gate cross section area is greater than the separation distance between the smaller, second area and the gate cross section area. Therefore, the first capacitance is reduced because of the larger separation distance and the second capacitance is reduced because of the smaller second area. The smaller thickness of the second top spacer being closer to the fin allows dopants to diffuse a shorter distance when forming a junction between the top S/D and the channel of the VFET.

Embodiments of the present invention are directed to a semiconductor structure and a method for forming a semiconductor structure having a self-aligned dielectric pillar for reducing trench silicide-to-gate parasitic capacitance. In a non-limiting embodiment of the invention, a nanosheet stack is formed over a substrate. A dielectric pillar is positioned adjacent to the nanosheet stack and on a shallow trench isolation region of the substrate. The nanosheet stack is recessed to expose a surface of the shallow trench isolation region and a source or drain (S/D) region is formed on the exposed surface of the shallow trench isolation region. A contact trench is formed that exposes a surface of the S/D region and a surface of the dielectric pillar.

Embodiments of the present invention are directed to a semiconductor structure and a method for forming a semiconductor structure having a self-aligned dielectric pillar for reducing trench silicide-to-gate parasitic capacitance. In a non-limiting embodiment of the invention, a nanosheet stack is formed over a substrate. A dielectric pillar is positioned adjacent to the nanosheet stack and on a shallow trench isolation region of the substrate. The nanosheet stack is recessed to expose a surface of the shallow trench isolation region and a source or drain (S/D) region is formed on the exposed surface of the shallow trench isolation region. A contact trench is formed that exposes a surface of the S/D region and a surface of the dielectric pillar.

The present invention provides a method and a system based on a multi-gate field effect transistor for sensing molecules in a gas or liquid sample. The said FET transistor comprises dual gate lateral electrodes (and optionally a back gate electrode) located on the two sides of an active region, and a sensing surface on top of the said active region. Appling voltages to the lateral gate electrodes, creates a conductive channel in the active region, wherein the width and the lateral position of the said channel can be controlled. Enhanced sensing sensitivity is achieved by measuring the channels conductivity at a plurality of positions in the lateral direction. The use of an array of the said FTE for electronic nose is also disclosed.

The present invention provides a method and a system based on a multi-gate field effect transistor for sensing molecules in a gas or liquid sample. The said FET transistor comprises dual gate lateral electrodes (and optionally a back gate electrode) located on the two sides of an active region, and a sensing surface on top of the said active region. Appling voltages to the lateral gate electrodes, creates a conductive channel in the active region, wherein the width and the lateral position of the said channel can be controlled. Enhanced sensing sensitivity is achieved by measuring the channels conductivity at a plurality of positions in the lateral direction. The use of an array of the said FTE for electronic nose is also disclosed.