Self-aligned interdigitated diffusion process for back-contact solar cell

• Main Authors: Tai-Hsin Lee, 李泰鑫
• Other Authors: San-Liang Lee
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/87915430258964719880

碩士 === 國立臺灣科技大學 === 電子工程系 === 102 === Due to both polarities of the metal electrodes on the rear side of the device, IBC solar cell exhibits some advantages over the conventional solar cell with metal contacts on both sides, such as increased short circuit current and improved series resistance. In the thesis self–aligned diffusion processes for intedigitated back- contact solar cell were studied. The fabrication of IBC solar cell includes six main steps: formation of N+ diffusion layer, electrical isolation, formation P+ contact layer, metallization, substrate thinning, and device characterization. We obtain a sheet resistance of 19Ω/sq by lifting the temperature at 900°C for 30min for emitter formation. Electrical isolation is done by realizing deep trenches between metal fingers with 30% KOH etching process. The etching depth is about 7.7μm with smooth surface. By thinning down the substrate from 280μm to 140 μm, the short circuit current of the solar cell increase due to finite carrier lifetime of the substrate. As-realized IBC solar cell has a short circuit current density of 22.75 mA/cm2, a open-circuit voltage of 554mV, a filling factor of 44.02%, and a ultimate efficiency of 5.5%.