Abstract: Solar cells fabricated without gasification of metallurgical-grade silicon. The substrates are prepared by: melting metallurgical grade silicon in a furnace; solidifying the melted metallurgical grade silicon into an ingot; slicing the ingot to obtain a plurality of wafers; polishing and cleaning each wafer; depositing aluminum layer on backside of each wafer; depositing a layer of hydrogenated silicon nitride on front surface of each wafer; annealing the wafers at elevated temperature; removing the hydrogenated silicon nitride; and, removing the aluminum layer. The front surface may be textured prior to forming the solar cell. The solar cell structure comprises a metallurgical grade doped silicon substrate and a thin-film structure formed over the substrate to form a p-i-n junction with the substrate. The substrate may be doped p-type, and the thin film structure may be an intrinsic amorphous layer formed over the substrate and an n-type amorphous layer formed over the intrinsic layer.

Abstract: In one embodiment, a method for forming a tungsten-containing material on a substrate is provided which includes forming a tungsten-containing layer by sequentially exposing a substrate to a processing gas and a tungsten-containing gas during an atomic layer deposition process, wherein the processing gas comprises a boron-containing gas and a nitrogen-containing gas, and forming a tungsten bulk layer over the tungsten-containing layer by exposing the substrate to a deposition gas comprising the tungsten-containing gas and a reactive precursor gas during a chemical vapor deposition process. In one example, the tungsten-containing layer and the tungsten bulk layer are deposited within the same processing chamber.

Abstract: In one embodiment, a method for forming a tungsten material on a substrate surface is provide which includes positioning a substrate within a deposition chamber, heating the substrate to a deposition temperature, and exposing the substrate sequentially to diborane and a tungsten precursor gas to form a tungsten nucleation layer on the substrate during an atomic layer deposition (ALD) process. The method further provides exposing the substrate to a deposition gas comprising hydrogen gas and the tungsten precursor gas to form a tungsten bulk layer over the tungsten nucleation layer during a chemical vapor deposition (CVD) process. Examples are provided which include ALD and CVD processes that may be conducted in the same deposition chamber or in different deposition chambers.

Abstract: In one embodiment, a method for forming a tungsten-containing material on a substrate is provided which includes forming a tungsten-containing layer by sequentially exposing a substrate to a processing gas and a tungsten-containing gas during an atomic layer deposition process, wherein the processing gas comprises a boron-containing gas and a nitrogen-containing gas, and forming a tungsten bulk layer over the tungsten-containing layer by exposing the substrate to a deposition gas comprising the tungsten-containing gas and a reactive precursor gas during a chemical vapor deposition process. In one example, the tungsten-containing layer and the tungsten bulk layer are deposited within the same processing chamber.

Abstract: Methods for fabricating solar cells without the need to perform gasification of metallurgical-grade silicon are disclosed. Consequently, the costs and health and environmental hazards involved in fabricating the solar or silicon grade silicon are being avoided. A solar cell structure comprises a metallurgical grade doped silicon substrate and a thin-film structure formed over the substrate to form a p-i-n junction with the substrate. The substrate may be doped p-type, and the thin film structure may be an intrinsic amorphous layer formed over the substrate and an n-type amorphous layer formed over the intrinsic layer.

Abstract: Methods for fabricating solar cells without the need to perform gasification of metallurgical-grade silicon are disclosed. Consequently, the costs and health and environmental hazards involved in fabricating the solar or silicon grade silicon are being avoided. A solar cell structure comprises a metallurgical grade doped silicon substrate and a thin-film structure formed over the substrate to form a p-i-n junction with the substrate. The substrate may be doped p-type and the thin film structure may be an intrinsic.

Abstract: A moisture sensor is disclosed which measures cumulative exposure to moisture. The moisture sensor comprises a matrix having a hygroscopic material, a first reagent, and a second reagent which interact only in the presence of water to produce a detectable, irreversible change in the matrix to provide a moisture indication. The moisture sensor may be incorporated with a disposable diagnostic device, whereby a method for preventing the use of such a disposable diagnostic device if exposed to excessive cumulative humidity is also disclosed.

Abstract: In one embodiment, a method for forming a tungsten-containing material on a substrate is provided which includes forming a tungsten-containing layer by sequentially exposing a substrate to a processing gas and a tungsten-containing gas during an atomic layer deposition process, wherein the processing gas comprises a boron-containing gas and a nitrogen-containing gas, and forming a tungsten bulk layer over the tungsten-containing layer by exposing the substrate to a deposition gas comprising the tungsten-containing gas and a reactive precursor gas during a chemical vapor deposition process. In one example, the tungsten-containing layer and the tungsten bulk layer are deposited within the same processing chamber.

Abstract: In one embodiment, a method for forming a tungsten material on a substrate surface is provide which includes positioning a substrate within a deposition chamber, heating the substrate to a deposition temperature, and exposing the substrate sequentially to diborane and a tungsten precursor gas to form a tungsten nucleation layer on the substrate during an atomic layer deposition (ALD) process. The method further provides exposing the substrate to a deposition gas comprising hydrogen gas and the tungsten precursor gas to form a tungsten bulk layer over the tungsten nucleation layer during a chemical vapor deposition (CVD) process. Examples are provided which include ALD and CVD processes that may be conducted in the same deposition chamber or in different deposition chambers.

Abstract: A substrate is processed in a process chamber comprising a substrate support having a receiving surface for receiving a substrate so that a front surface of the substrate is exposed within the chamber. An energized process gas is used to process the front surface of the substrate. A peripheral edge of the backside surface of the substrate is cleaned by raising the substrate above the receiving surface of the substrate support to a raised position, and exposing the backside surface of the substrate to an energized cleaning gas.

Abstract: In one embodiment, a method for forming a tungsten material on a substrate surface is provide which includes positioning a substrate within a deposition chamber, heating the substrate to a deposition temperature, and exposing the substrate sequentially to diborane and a tungsten precursor gas to form a tungsten nucleation layer on the substrate during an atomic layer deposition (ALD) process. The method further provides exposing the substrate to a deposition gas comprising hydrogen gas and the tungsten precursor gas to form a tungsten bulk layer over the tungsten nucleation layer during a chemical vapor deposition (CVD) process. Examples are provided which include ALD and CVD processes that may be conducted in the same deposition chamber or in different deposition chambers.

Abstract: A plasma etch process for etching a porous carbon-doped silicon oxide dielectric layer using a photoresist mask is carried out first in an etch reactor by performing a fluorocarbon based etch process on the workpiece to etch exposed portions of the dielectric layer while depositing protective fluorocarbon polymer on the photoresist mask. Then, in an ashing reactor, polymer and photoresist are removed by heating the workpiece to over 100 degrees C., exposing a peripheral portion of the backside of said workpiece, and providing products from a plasma of a hydrogen process gas to reduce carbon contained in polymer and photoresist on said workpiece until the polymer has been removed from a backside of said workpiece. The process gas preferably contains both hydrogen gas and water vapor, although the primary constituent is hydrogen gas. The wafer (workpiece) backside may be exposed by extending the wafer lift pins.

Abstract: In one embodiment, a method for forming a tungsten-containing material on a substrate is provided which includes forming a tungsten-containing layer by sequentially exposing a substrate to a processing gas and a tungsten-containing gas during an atomic layer deposition process, wherein the processing gas comprises a boron-containing gas and a nitrogen-containing gas, and forming a tungsten bulk layer over the tungsten-containing layer by exposing the substrate to a deposition gas comprising the tungsten-containing gas and a reactive precursor gas during a chemical vapor deposition process. In one example, the tungsten-containing layer and the tungsten bulk layer are deposited within the same processing chamber.

Abstract: Active mixing by magnetic stirring is demonstrated inside a picoliter-size liquid droplet. Magnetic microspheres are added to the droplet, which form aligned chains under the influence of a homogeneous magnetic field. When the magnetic field is rotated, the chains also rotate synchronously. Viscous interaction between the particle-chains and the liquid induces advective motion inside the droplet thereby enhancing mixing which is otherwise diffusion-limited. The concept can be effectively used to create a lab-in-a-droplet for MEMS (Micro-Electrical-Mechanical Systems) and Bio-MEMS applications.

Abstract: In one embodiment, a method for forming a tungsten material on a substrate surface is provide which includes positioning a substrate within a deposition chamber, heating the substrate to a deposition temperature, and exposing the substrate sequentially to a first reducing gas and a tungsten precursor gas to form a tungsten nucleation layer on the substrate during an atomic layer deposition (ALD) process. The method may further provide exposing the substrate to a deposition gas comprising a second reducing gas and the tungsten precursor gas to form a tungsten bulk layer on the tungsten nucleation layer during a chemical vapor deposition (CVD) process. Examples include that the ALD and CVD processes are conducted in the same deposition chamber or in different deposition chambers.

Abstract: In one embodiment, a method for forming a tungsten-containing material on a substrate is provided which includes forming a tungsten nucleation layer by sequentially exposing a substrate to a boron-containing gas and a tungsten-containing gas within a processing chamber during an atomic layer deposition process, and forming a tungsten bulk layer on the tungsten nucleation layer by exposing the substrate to a processing gas that contains the tungsten-containing gas and a reactive precursor gas within another processing chamber during a chemical vapor deposition process. In one example, the tungsten nucleation layer is deposited on a dielectric material, such as silicon oxide. In another example, the tungsten nucleation layer is deposited on a barrier material, such as titanium or titanium nitride. Other examples provide that the tungsten nucleation layer and the tungsten bulk layer are deposited in the same processing chamber.

Abstract: A multi-step sputtering process in plasma sputter reactor having target and magnetron operable in two modes, for example, in a substrate sputter etch and a substrate sputter deposition. The target has an annular vault facing the wafer to be sputter coated. Various types of magnetic means positioned around the vault create a magnetic field supporting a plasma extending over a large volume of the vault. An integrated copper via filling process with the inventive reactor or other reactor includes a first step of highly ionized sputter deposition of copper, which can optionally be used to remove the barrier layer at the bottom of the via, a second step of more neutral, lower-energy sputter deposition of copper to complete the seed layer, and a third step of electroplating copper into the hole to complete the metallization. The first two steps can be also used with barrier metals.

Abstract: In some implementations, a method is provided in a plasma processing chamber for stabilizing etch-rate distributions during a process transition from one process step to another process step. The method includes performing a pre-transition compensation of at least one other process parameter so as to avoid unstable plasma states by inhibiting formation of a parasitic plasma during the process transition. In some implementations, a method is provided for processing a workpiece in plasma processing chamber, which includes inhibiting deviations from an expected etch-rate distribution by avoiding unstable plasma states during a process transition from one process step to another process step.

Abstract: In some implementations, a method is provided for inhibiting charge damage in a plasma processing chamber during a process transition from one process step to another process step, including performing a pre-transition compensation of at least one process parameter so as to inhibit charge damage from occurring during the process transition. In some implementations, a method is provided for inhibiting charge damage during a process transition from one process step to another process step, which includes changing at least one process parameter with a smooth non-linear transition. In some implementations, a method is provided which includes sequentially changing selected process parameters such that a plasma is able to stabilize after each change prior to changing a next selected process parameter.

Abstract: A method and apparatus for processing a substrate includes a reactor chamber having a chamber wall and containing a substrate support. An electrode overlies the substrate and is spaced apart from the substrate support. One or more plasma sources maintains plasma in the reactor in one or more toroidal paths using a first frequency. One or more RF power generators supply power to the electrode at a second frequency that is different from the first frequency.