A solar cell comprising a bulk germanium silicon growth substrate; a diffused photoactive junction in the germanium silicon substrate; and a sequence of subcells grown over the substrate, with the first grown subcell either being lattice matched or lattice mis-matched to the growth substrate.

A method for forming a gate stack of a field-effect transistor includes depositing a Si capping layer on a Ge channel material (100). The method further includes depositing an oxide layer on the Si capping layer by a plasma enhanced deposition technique at a temperature less than or equal to 200 C., and a plasma power less than or equal to 100 W.

A semiconductor device includes a field-effect transistor, a first back-end-of-line (BEOL) metallization level and a second BEOL metallization level disposed above the first BEOL metallization level. A portion of the field-effect transistor includes lithium therein, and the field-effect transistor is integrated between the first and second BEOL metallization levels. The portion of the field-effect transistor including the lithium therein can be a channel layer, or a source and/or drain region.

A semiconductor structure and a method for fabricating the same. The structure includes a substrate and at least one semiconductor fin. The semiconductor structure further includes a channel region within the semiconductor fin. The channel region includes a higher content of germanium than remaining portions of the semiconductor fin. The semiconductor structure also includes a gate stack in contact with the semiconductor fin. The method includes removing a dummy gate formed on at least one semiconductor fin. The removal of the dummy gate exposes a channel region of the semiconductor fin. A germanium dioxide layer is formed in contact with the channel region. A condensation process is performed after the germanium dioxide layer has been formed. The condensation process increases germanium content only in the channel region.

In a method of manufacturing a semiconductor device, a single crystal oxide layer is formed over a substrate. After the single crystal oxide layer is formed, an isolation structure to define an active region is formed. A gate structure is formed over the single crystal oxide layer in the active region. A source/drain structure is formed.

A method of forming a structure including a silicon nitride overlying a titanium nitride layer is disclosed. The method includes forming the titanium nitride layer and the silicon nitride layer in the same reaction chambere.g., without a vacuum breakto mitigate oxidation of the titanium nitride layer that might otherwise occur.

The disclosed technology generally relates to semiconductor devices, and more particularly to transistors comprising germanium (Ge) in the channel, and to methods of manufacturing thereof. In one aspect, a field-effect transistor (FET) comprises an active region comprising germanium (Ge) and a gate stack formed on the active region. The gate stack comprises a Si-comprising passivation layer formed on the active region, an interfacial dielectric layer comprising SiO.sub.x (x>0) formed on the passivation layer, a dielectric capping layer comprising an interface dipole-forming material formed on the interfacial dielectric layer, a high-k dielectric layer formed on the dielectric capping layer and a gate electrode layer formed on the high-k dielectric layer.

Device structures for a field-effect transistor and methods of forming a device structure for a field-effect transistor. A channel region is arranged laterally between a first source/drain region and a second source/drain region. The channel region includes a first semiconductor layer and a second semiconductor layer arranged over the first semiconductor layer. A gate structure is arranged over the second semiconductor layer of the channel region The first semiconductor layer is composed of a first semiconductor material having a first carrier mobility. The second semiconductor layer is composed of a second semiconductor material having a second carrier mobility that is greater than the first carrier mobility of the first semiconductor layer.

Embodiments herein describe techniques for a semiconductor device including a Ge substrate. A passivation layer may be formed above the Ge substrate, where the passivation layer may include one or more molecular monolayers with atoms of one or more group 15 elements or group 16 elements. In addition, a low-k interlayer may be above the passivation layer, and a high-k interlayer may be above the low-k interlayer. Furthermore, a metal contact may be above the high-k interlayer. Other embodiments may be described and/or claimed.

An apparatus including a substrate; a transistor device on the substrate including a channel and a source and a drain disposed between the channel; a source contact coupled to the source and a drain contact coupled to the drain; and the source and drain each including a composition including a concentration of germanium at an interface with the channel that is greater than a concentration of germanium at a junction with the source contact. A method including defining an area on a substrate for a transistor device; forming a source and a drain each including an interface with the channel; and forming a contact to one of the source and the drain, wherein a composition of each of the source and the drain includes a concentration of germanium at an interface with the channel that is greater than a concentration at a junction with the contact.