Study of Pd/Au Ohmic Contact on P-Type Ge and Its Application to GaAs/Ge Dual-Junction Solar Cells

• Main Authors: Chih-Chao Yang, 楊智超
• Other Authors: Chih-Hung Wu
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/30881542969581694603

碩士 === 中原大學 === 電子工程研究所 === 99 === Abstract In this dissertation, we discussed the effects of thickness Pd on the Pd / Au and Pd / Ag / Au ohmic contact metallurgical structure deposited on P-Ge material. At first ,we studied the optimum thickness of the Pd layer and the suitable annealing temperature and time for obtaining the lowest specific contact resistance ρc on P-Ge by transmission line model method (TLM).We found out that the optimum metallurgical structure is Pd (30 nm) / Au (60 nm) after annealed at 350 ℃ for 2 minutes. The lowest value ρc=6×10-6 Ω-cm2 of specific contact resistance could be attained. Then, we used the same method to study the optimum thickness of the Pd、Ag and Au layers and the suitable annealing temperature and time for the lowest specific contact resistance ρc. We found out that the optimum metallurgical structure is Pd (20 nm) / Ag (60 nm) / Au (20 nm), in which the lowest specific contact resistance value ρc=3.9×10-5 Ω-cm2 could be attained when the sample is annealed at 350℃ for 2 minutes. Then, we applied the optimum ohmic contact metallurgical structure Pd (30 nm) /Au (60 nm) and Pd (20 nm) / Ag (60 nm) / Au (20nm), respectively, as the p-type ohmic contact of dual-junction (DJ) solar cells. After that, we measured the efficiency (Eff), fill factor (FF), open circuit voltage (Voc) and short circuit current (Isc) of solar cells. The measured results indicate that solar cells had the best performance when having the ohmic contact fabricated at the optimum conditions.