Table 1: Primary and Secondary Performance Requirements Enough current to Cells must Produce a minimum power a low current Primary Requirements connect with of 2.5V device, such as an low resistance LED Transfer power Packaging must be Packaging should be Secondary Requirements to charging portable, handheld transparent circuitry CONCEPTUAL DESIGN To address the disconnect issue identified by last year’s team, our design solution involves depositing the aluminum contacts on top of an insulating SU-8 layer which will be sequestering the cells from one another. This will eliminate the need for the aluminum to maintain a continuous connection across a corner. Our design solution solves the shorting problem by doping the p-type regions out to the edges of each cell. An iteration of this design solution is shown below (Fig 6). Figure 6: The SU-8 layer isolates the cells and supports the interconnects. The p-regions are positioned to eliminate the possibility of a short. MICRO-FABRICATION PROCESSES FOR SOLAR CELLS We proposed two methods of processing to fabricate solar cell arrays. Both of the methods involve the formation of aluminum interconnects on top of an insulating SU-8 channel in order to connect the cells in the array. In the first method, the p-n junction is created first and the channels are formed after. In the second method, the channel is created before the p-n junction is doped and diffused. This method requires an additional cycle in the furnace. See Appendices A and B for full process descriptions. The choice in final method was based upon the inherent risks present in each method.
Table 1: Primary and Secondary Performance Requirements Primary Requirements Cells must connect with low resistance Produce a minimum of 2.5V Enough current to power a low current device, such as an LED Secondary Requirements Transfer power to charging circuitry Packaging must be portable, handheld Packaging should be transparent CONCEPTUAL DESIGN To address the disconnect issue identified by last year’s team, our design solution involves depositing the aluminum contacts on top of an insulating SU-8 layer which will be sequestering the cells from one another. This will eliminate the need for the aluminum to maintain a continuous connection across a corner. Our design solution solves the shorting problem by doping the p-type regions out to the edges of each cell. An iteration of this design solution is shown below (Fig 6). Figure 6: The SU-8 layer isolates the cells and supports the interconnects. The p-regions are positioned to eliminate the possibility of a short. MICRO-FABRICATION PROCESSES FOR SOLAR CELLS We proposed two methods of processing to fabricate solar cell arrays. Both of the methods involve the formation of aluminum interconnects on top of an insulating SU-8 channel in order to connect the cells in the array. In the first method, the p-n junction is created first and the channels are formed after. In the second method, the channel is created before the p-n junction is doped and diffused. This method requires an additional cycle in the furnace. See Appendices A and B for full process descriptions. The choice in final method was based upon the inherent risks present in each method.
Detailed-Design-Review-1305408953.docx