Abstract:
A polarization resistant solar cell is provided. The solar cell (200) uses a dual layer dielectric stack disposed on the front surface of the cell. The dielectric stack consists of a passivation layer (209) disposed directly on the front cell surface and comprised of either SiO x or SiON, and an outer AR coating (211) comprised of SiCN.
Abstract:
Techniques are here disclosed for a solar cell pre-processing method and system for annealing and gettering a solar cell semiconductor wafer having an undesirably high dispersion of transition metals, impurities and other defects. The process forms a surface contaminant layer on the solar cell semiconductor (e.g., silicon) wafer. A surface of the semiconductor wafer receives and holds impurities, as does the surface contaminant layer. The lower-quality semiconductor wafer includes dispersed defects that in an annealing process getter from the semiconductor bulk to form impurity cluster toward the surface contaminant layer. The impurity clusters form within the surface contaminant layer while increasing the purity level in wafer regions from which the dispersed defects gettered. Cooling follows annealing for retaining the impurity clusters and, thereby, maintaining the increased purity level of the semiconductor wafer in regions from which the impurities gettered. Multicrystalline semiconductor wafers having grain boundaries with impurities may also undergo the annealing and gettering of dispersed defects to the grain boundaries, further increasing the semiconductor substrate purity levels.
Abstract:
A polarization resistant solar cell using an oxygen-rich interface layer is provided. The oxygen-rich interface layer may be comprised of SiO x N y , which may have a graded profile that varies between oxygen-rich proximate to the solar cell to nitrogen-rich distal to the solar cell. A silicon oxide passivation layer may be interposed between the solar cell and the SiO x N y graded dielectric layer. The graded SiO x N y dielectric layer may be replaced with a non-graded SiO x N y dielectric layer and a SiN AR coating.
Abstract translation:提供了使用富氧界面层的耐极化太阳能电池。 富氧界面层可以由SiO x N y组成,其可以具有在太阳能电池附近的富含氧和太阳能电池远端富氮之间变化的分级分布。 氧化硅钝化层可以介于太阳能电池和SiO x N y梯度电介质层之间。 分级的SiO x N y介电层可以用非梯度的SiO x N y电介质层和SiN-AR涂层代替。
Abstract:
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 (107) located on the front surface of the substrate (101), formed for example by a phosphorous diffusion step. The back surface includes a doped region (103), the doped region having the same conductivity as the substrate but with a higher doping level. Contact grids (111/113) are formed, for example by screen printing. Front junction isolation is accomplished using a laser scribe.
Abstract:
Techniques for the formation of silicon ingots and crystals using silicon feedstock of various grades are described. Common feature is adding a predetermined amount of germanium to the melt and performing a crystallization to incorporate germanium into the silicon lattice of respective crystalline silicon materials. Such incorporated germanium results in improvements of respective silicon material characteristics, mainly increased material strength. This leads to positive effects at applying such materials in solar cell manufacturing and at making modules from those solar cells. A silicon material with a germanium concentration in the range (50-200) ppmw demonstrates an increased material strength, where best practical ranges depend on the material quality generated.
Abstract:
Techniques for the formation of a large grain, multi-crystalline semiconductor ingot and include forming a silicon melt in a crucible, the crucible capable of locally controlling thermal gradients within the silicon melt. The local control of thermal gradients preferentially forms silicon crystals in predetermined regions within the silicon melt by locally reducing temperatures is the predetermined regions. The method and system control the rate at which the silicon crystals form using local control of thermal gradients for inducing the silicon crystals to obtain preferentially maximal sizes and, thereby, reducing the number of grains for a given volume. The process continues the thermal gradient control and the rate control step to form a multi crystalline silicon ingot having reduced numbers of grains for a given volume of the silicon ingot.
Abstract:
Techniques for the formation of a higher purity semiconductor ingot using a low purity semiconductor feedstock include associating within a crucible a low-grade silicon feedstock, which crucible forms a process environment of said molten silicon. The process associates with the low-grade silicon feedstock, a quantity of the at least one metal and includes forming within the crucible a molten solution (e.g., a binary or ternary solution) of molten silicon and the metal at a temperature below the melting temperature of said low-grade silicon feedstock. A silicon seed crystal associates with the molten solution within the crucible for inducing directional silicon crystallization. The process further forms a silicon ingot from a portion of the molten solution in association with the silicon seed. The silicon ingot includes at least one silicon crystalline formation grown in the induced directional silicon crystallization process. The resulting silicon ingot has a silicon purity substantially exceeding the silicon purity of said low grade silicon feedstock.
Abstract:
A polarization resistant solar cell using an oxygen-rich interface layer (209) is provided. The oxygen-rich interface layer may be comprised of SiOxNy, which may have a graded profile that varies between oxygen-rich proximate to the solar cell to nitrogen-rich distal to the solar cell. A silicon oxide passivation layer (601) may be interposed between the solar cell and the SiOxNy graded dielectric layer. The graded SiOxNy dielectric layer may be replaced with a non-graded SiOxNy dielectric layer and a SiN AR coating (703).
Abstract translation:提供了使用富氧界面层(209)的耐极化太阳能电池。 富氧界面层可以由SiO x N y组成,其可以具有在太阳能电池附近的富含氧和太阳能电池远端富氮之间变化的分级分布。 氧化硅钝化层(601)可以介于太阳能电池和SiO x N y梯度电介质层之间。 分级的SiO x N y介电层可以用非梯度的SiO x N y介电层和SiN-AR涂层(703)代替。
Abstract:
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.
Abstract:
Techniques for controlling resistivity in the formation of a silicon ingot from compensated feedstock silicon material prepares a compensated, upgraded metallurgical silicon feedstock for being melted to form a silicon melt. The compensated, upgraded metallurgical silicon feedstock provides a predominantly p-type semiconductor for which the process assesses the concentrations of boron and phosphorus and adds a predetermined amount of aluminum or/and gallium. The process further melts the silicon feedstock together with a predetermined amount of aluminum or/and gallium to form a molten silicon solution from which to perform directional solidification and, by virtue of adding aluminum or/and gallium, maintains the homogeneity the resistivity of the silicon ingot throughout the silicon ingot. In the case of feedstock silicon leading to low resistivity in respective ingots, typically below 0.4 Ωcm, a balanced amount of phosphorus can be optionally added to aluminum or/and gallium. Adding phosphorus becomes mandatory at very low resistivity, typically close to 0.2 Ωcm and slightly below.