Fin Field Effect Transistor (FET) (FinFET) complementary metal oxide semiconductor (CMOS) circuits with single and double diffusion breaks for increased performance are disclosed. In one aspect, a FinFET CMOS circuit employing single and double diffusion breaks includes a P-type FinFET that includes a first Fin formed from a semiconductor substrate and corresponding to a P-type diffusion region. The FinFET CMOS circuit includes an N-type FinFET that includes a second Fin formed from the semiconductor substrate and corresponding to an N-type diffusion region. To electrically isolate the P-type FinFET, first and second single diffusion break (SDB) isolation structures are formed in the first Fin on either side of a gate of the P-type FinFET. To electrically isolate the N-type FinFET, first and second double diffusion break (DDB) isolation structures are formed in the second Fin on either side of a gate of the N-type FinFET.

The present disclosure provides many different embodiments of a FinFET device that provide one or more improvements over the prior art. In one embodiment, a FinFET includes a semiconductor substrate and a plurality of fins having a first height and a plurality of fin having a second height on the semiconductor substrate. The second height may be less than the first height.

A representative fin field effect transistor (FinFET) includes a substrate having a major surface; a fin structure protruding from the major surface having a lower portion comprising a first semiconductor material having a first lattice constant; an upper portion comprising the first semiconductor material. A bottom portion of the upper portion comprises a dopant with a first peak concentration. A middle portion is disposed between the lower portion and upper portion, where the middle portion comprises a second semiconductor material having a second lattice constant different from the first lattice constant. An isolation structure surrounds the fin structure, where a portion of the isolation structure adjacent to the bottom portion of the upper portion comprises the dopant with a second peak concentration equal to or greater than the first peak concentration.

A representative fin field effect transistor (FinFET) includes a substrate having a major surface; a fin structure protruding from the major surface having a lower portion comprising a first semiconductor material having a first lattice constant; an upper portion comprising the first semiconductor material. A bottom portion of the upper portion comprises a dopant with a first peak concentration. A middle portion is disposed between the lower portion and upper portion, where the middle portion comprises a second semiconductor material having a second lattice constant different from the first lattice constant. An isolation structure surrounds the fin structure, where a portion of the isolation structure adjacent to the bottom portion of the upper portion comprises the dopant with a second peak concentration equal to or greater than the first peak concentration.

Embodiments of the present invention provide a semiconductor structure having a strain relaxed buffer, and method of fabrication. A strain relaxed buffer is disposed on a semiconductor substrate. A silicon region and silicon germanium region are disposed adjacent to each other on the strain relaxed buffer. An additional region of silicon or silicon germanium provides quantum well isolation.

An embodiment includes a microelectronic device comprising: a substrate comprising a raised portion and a non-raised portion, wherein a dielectric material is disposed adjacent the raised portion, an epitaxial sub-fin structure disposed on the raised portion, wherein a bottom portion of the epitaxial sub-fin structure comprises an asymmetric profile, and an epitaxial fin device structure disposed on the sub-fin structure. Other embodiments are described herein.

A method for forming spacers of a gate of a field effect transistor is provided, the gate including sides and a top and being located above a layer of a semiconductor material, the method including a step of forming a dielectric layer that covers the gate; after the step of forming the dielectric layer, at least one step of modifying the dielectric layer by ion implantation while retaining non-modified portions of the dielectric layer covering sides of the gate and being at least non-modified over their entire thickness; the ions having a hydrogen base and/or a helium base; at least one step of removing the modified dielectric layer using a selective etching of the dielectric layer, wherein the removing includes a wet etching with a base of a solution including hydrofluoric acid diluted to x % by weight, with x≦0.2, and having a pH less than or equal to 1.5.

A method includes receiving a substrate having a front surface and a back surface; forming an isolation feature of a first dielectric material in the substrate, thereby defining an active region surrounded by the isolation feature; forming a gate stack on the active regions; forming a first and a second S/D feature on the fin active region; forming a front contact feature contacting the first S/D feature; thinning down the substrate from the back surface such that the isolation feature is exposed; selectively etching the active region, resulting in a trench surrounded by the isolation feature, the second S/D feature being exposed within the trench; forming, in the trench, a liner layer of a second dielectric material being different from the first dielectric material; forming a backside via feature landing on the second S/D feature within the trench; and forming a backside metal line landing on the backside via feature.

Some embodiments of the present disclosure are directed to a device. The device includes a substrate comprising a silicon layer disposed over an insulating layer. The substrate includes a transistor device region and a radio-frequency (RF) region. An interconnect structure is disposed over the substrate and includes a plurality of metal layers disposed within a dielectric structure. A handle substrate is disposed over an upper surface of the interconnect structure. A trapping layer separates the interconnect structure and the handle substrate.

An SOI semiconductor device includes a first wafer having an active semiconductor layer and a first oxide layer and a second wafer having a semiconductor substrate and a second oxide layer, the first oxide layer being bonded to the second oxide layer, and one of the first wafer and the second wafer includes a nitride layer. The nitride layer can be formed between the semiconductor substrate and the second oxide layer. A third oxide layer can be formed on the semiconductor substrate and the nitride layer is formed between the second oxide layer and the third oxide layer. The nitride layer can be formed between the active semiconductor layer and the first oxide layer. The first wafer can include a third oxide layer formed on the active semiconductor layer and the nitride layer is formed between the third oxide layer and the first oxide layer.