TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Method: In the solar cell formation, the layer comprises a conductive material, the substrate comprises silicon, and the patterned doped region has a dopant concentration greater than about 1x1018 atoms/cm3. Receiving electromagnetic radiation at a first wavelength is performed by an optical detector that is positioned adjacent to the first surface and the emitted electromagnetic radiation is provided to a second surface that is opposite the first surface. Determining the actual position of the patterned doped region comprises capturing an optical image of two or more alignment marks disposed on a surface of the substrate, and determining the difference in position of each of alignment marks to an ideal position to determine the offset based on the optical image. The ideal position of the alignment marks is determined with respect to the at least one feature of the substrate prior to printing the first layer. At least three alignment marks are formed on the surface of the substrate using a screen printing process. Comparing the actual position of the alignment marks comprises constructing a first reference line between two of the alignment marks and constructing a second reference line between a third alignment mark and the first reference line, where the second reference line is perpendicular to the first reference line. Positioning a substrate on a substrate receiving surface comprises: receiving a substrate on a first surface of a support material; moving the support material across a surface of the substrate support using an actuator coupled to the supporting material; and evacuating a region behind the first surface of the support material to hold the substrate disposed on the first surface against the substrate support; and aligning features in a screen printing mask to the patterned doped region further comprises positioning the substrate held on the first surface of the support material under the screen printing mask. Determining the actual position of the patterned doped region on the substrate further comprises: positioning the substrate receiving surface or a screen printing mask so that a portion of the emitted electromagnetic radiation passes through one or more features formed in the screen printing mask and the first surface of the substrate disposed on the substrate receiving surface before it is received by a detector, where aligning the one or more features in a screen printing mask to the patterned doped region comprises adjusting the position of the feature formed in the screen printing mask to a portion of the patterned doped region formed on the substrate. The portion of the patterned doped region formed on the substrate comprises two or more nested elements that have a gap formed there between, where at least one of the two or more nested elements has a first width, and the feature formed in the screen printing mask has a second width that is smaller than the first width. Determining the actual position of the patterned doped region on the substrate further comprises detecting the variation in intensity of the emitted electromagnetic radiation received by the detector from two or more regions of the patterned doped region. Alternatively, the method comprises: disposing a masking material in a pattern on a first surface of a substrate; etching a portion of the first surface while the masking material is disposed on the first surface, where the masking material substantially inhibits the etching of regions of the first surface over which the masking material is disposed; capturing an optical image of a portion of the first surface; aligning features in a screen printing mask to at least a portion of the plurality of regions using the information received from the captured optical image; and depositing a layer of material through the features and onto at least a portion of the plurality of regions. The masking material comprises a first dopant material. It further comprises: heating the substrate and masking material to cause the first dopant material to diffuse into the first surface and form a patterned doped region, where heating the substrate and the masking material is performed after etching the portion of the first surface. It further comprises diffusing an amount of the first dopant material into a portion of the first surface after etching a portion of the first surface. Capturing an optical image of a portion of the first surface comprises capturing an optical image of two or more alignment marks disposed on a surface of the substrate, and determining the difference in position of each of alignment marks to an ideal position to determine the offset based on the optical image. The substrate comprises silicon and the patterned doped region has a dopant concentration greater than about 1x1018 atoms/cm3. It further comprises: heating the substrate and masking material to cause a first dopant material disposed in the masking material to diffuse into the first surface and form a patterned doped region, where capturing an optical image of a portion of the patterned doped region comprises: emitting electromagnetic radiation towards the first surface; and receiving electromagnetic radiation at a wavelength between about 850 nm and about 4 mu m from a region of the first surface. Capturing the optical image of the portion of the patterned doped region further comprises noting the difference in the intensity of the electromagnetic radiation reflected from or transmitted through a portion of the first surface that was covered by the masking layer and a portion of the first surface that was not covered by the masking layer during the process of etching a portion of the first surface. It further comprises: diffusing a first amount of a first dopant atom into the first surface of the substrate to form a first doped region before disposing the masking material on the first surface; and diffusing a second amount of a second dopant atom into the first surface to form a second doped region after disposing the masking material on the first surface and etching the portion of the first surface. The first dopant atom and second dopant atom are each selected from a group of elements consisting of phosphorus, arsenic antimony, boron, aluminum, and gallium. The first dopant atom and the second dopant atom are the same type of dopant atom, and the first amount of the first dopant atom in the first doped region is greater than the second amount of the second dopant atom in the second doped region. It also comprises: etching a portion of a first surface of a substrate; depositing a first layer over a portion of the etched first surface; removing a portion of the deposited first layer disposed over the etched first surface to expose a region of the substrate; delivering a dopant containing material to the exposed region of the substrate to form a doped region within the substrate; capturing an image of a portion of the first surface of the substrate, where the image comprises a portion of the exposed region and a portion of the etched first surface; aligning features in a screen printing mask to the exposed region using information received from the captured image; and depositing a layer of material through the features and onto at least a portion of the patterned doped region after they are aligned to the exposed region. Capturing an image of a portion of the first surface comprises capturing an optical image of two or more alignment marks disposed on a surface of the substrate, and determining the difference in position of each of alignment marks to an ideal position to determine the offset based on the optical image. Capturing an optical image of a portion of the patterned doped region comprises: emitting electromagnetic radiation towards the first surface; and receiving electromagnetic radiation at a wavelength between about 850 nm and about 4 mu m from a region of the first surface. The second layer disposed over the first surface of the substrate over the second layer, where the second layer comprises group consisting of silicon nitride (SiN) and silicon dioxide comprises amorphous silicon (a-Si). Preferred Apparatus: In the apparatus, the substrate support is part of a material conveyor assembly that comprises a first material positioning mechanism that is adapted to provide a supporting material to a platen, where the supporting material comprises the substrate supporting surface that is disposed on a side of the supporting material that is opposite to another side of the supporting material which is in contact with a surface of the platen. The first surface of the supporting material is positioned on the substrate supporting surface, and the supporting material comprises a porous material that allows air to pass from a second surface to the first surface when a vacuum is applied to the first surface. The electromagnetic radiation source is mounted proximate to a first side of the substrate supporting surface, and the detector assembly is mounted on a side opposite to the first side. The detector assembly comprises a camera and at least one optical filter disposed between the substrate supporting surface and the camera, where the optical filter is adapted to allow the wavelength to pass there through.