| Patent application number | Description | Published |
|---|
| 20090223549 | SOLAR CELL AND FABRICATION METHOD USING CRYSTALLINE SILICON BASED ON LOWER GRADE FEEDSTOCK MATERIALS - Formation of a solar cell device from upgraded metallurgical grade silicon which has received at least one defect engineering process and including a low contact resistance electrical path. An anti-reflective coating is formed on an emitter layer and back contacts are formed on a back surface of the bulk silicon substrate. This photovoltaic device may be fired to form a back surface field at a temperature sufficiently low to avoid reversal of previous defect engineering processes. The process further forms openings in the anti-reflective coating and a low contact resistance metal layer, such as nickel layer, over the openings in the anti-reflective coating. The process may anneal the low contact resistance metal layer to form n-doped portion and complete an electrically conduct path to the n-doped layer. This low temperature metallization (e.g., <700° C.) supports the use of UMG silicon for the solar device formation without the risk of reversing earlier defect engineering processes. | 09-10-2009 |
| 20100275983 | Bifacial solar cells with overlaid back grid surface - A simplified manufacturing process and the resultant bifacial solar cell (BSC) are provided, the simplified manufacturing process reducing manufacturing costs. The BSC includes an active region located on the front surface of the substrate, formed for example by a phosphorous diffusion step. After removing the PSG, assuming phosphorous diffusion, and isolating the front junction, dielectric layers are deposited on the front and back surfaces. Contact grids are formed, for example by screen printing. Prior to depositing the back surface dielectric, a metal grid may be applied to the back surface, the back surface contact grid registered to, and alloyed to, the metal grid during contact firing. | 11-04-2010 |
| 20100275984 | Bifacial solar cells with back surface doping - A simplified manufacturing process and the resultant bifacial solar cell (BSC) are provided, the simplified manufacturing process reducing manufacturing costs. The BSC includes an active region located on the front surface of the substrate, formed for example by a phosphorous diffusion step. The back surface includes a doped region, the doped region having the same conductivity as the substrate but with a higher doping level. Contact grids are formed, for example by screen printing. Front junction isolation is accomplished using a laser scribe. | 11-04-2010 |
| 20100275995 | Bifacial solar cells with back surface reflector - A simplified manufacturing process and the resultant bifacial solar cell (BSC) are provided, the simplified manufacturing process reducing manufacturing costs. The BSC includes a back surface contact grid and an overlaid blanket metal reflector. A doped amorphous silicon layer is interposed between the contact grid and the blanket layer. | 11-04-2010 |
| 20100310445 | Process Control For UMG-Si Material Purification - A process control method for UMG-Si purification by performing a directional solidification of molten UMG-Si to form a silicon ingot is described. The ingot is divided into bricks and the resistivity profile of each silicon brick is mapped. A crop line for removing the impurities concentrated and captured in the ingot during the directional solidification is calculated based on the resistivity map. The concentrated impurities are then removed by cropping each brick along that brick's calculated crop line. | 12-09-2010 |
| 20100327890 | QUALITY CONTROL PROCESS FOR UMG-SI FEEDSTOCK - A quality control process for determining the concentrations of boron and phosphorous in a UMG-Si feedstock batch is provided. A silicon test ingot is formed by the directional solidification of molten UMG-Si from a UMG-Si feedstock batch. The resistivity of the silicon test ingot is measured from top to bottom. Then, the resistivity profile of the silicon test ingot is mapped. From the resistivity profile of the silicon test ingot, the concentrations of boron and phosphorous of the UMG-Si silicon feedstock batch are calculated. Additionally, multiple test ingots may be grown simultaneously, with each test ingot corresponding to a UMG-Si feedstock batch, in a multi-crucible crystal grower. | 12-30-2010 |
