具高開路電壓之金氧半太陽能電池

Abstract

金氧半太陽能電池的結構中，以氧化層的品質和厚度控制為其重要。我們利用磁控濺鍍機沉積此超薄穿隧氧化層，其厚度由濺鍍的時間控制；薄膜的品質，則由濺鍍的工作壓力以及後續氫退火改善。 首先個別分析p型和n型的金氧半太陽能電池，一開始以半穿透的金屬薄膜當作載子收集層並且提高開路電壓，為了降低表面反射率及缺陷，我們利用氮化矽或氧化鋁鈍化層分別沉積在具有粗糙化結構的p型及n型矽基板上，來取代半穿透金屬薄膜。除此之外，鈍化層也會在半導體表面形成反轉層，使得金屬和半導體間獲得更大能障差，進而提高開路電壓。 為了更進一步提升開路電壓，藉由直接晶圓結合的方式將p型與n型接合形成疊合式金氧半太陽能電池，在標準光源AM1.5G的量測系統下，其開路電壓可達到720mV。

In MIS solar cells, the ultrathin insulating layer deposited by radio frequency sputtering plays an important role. Its thickness is controlled by sputtering duration time. The quality of thin film is enhanced by adjusting the working pressure of sputtering and H2 post-annealing. The p-type and n-type of MIS solar cells are first investigated. Initially, the semi-transparent metal as a carrier collection layer is used in order to get better open circuit voltage (Voc). Then, both SiNx and Al2O3 are the passivation layers. In order to reduce the surface reflection and defects, SiNx is deposited on textured silicon substrate of p-type and Al2O3 is deposited on that of n-type to replace the semi-transparent metal. In addition, passivation layers can also induce inversion layer at surfaces of semiconductor. The formation makes lager barrier height between the metal and semiconductor and therefore enhances the Voc. With the aim to further improve the Voc, the p-type and n-type silicon substrates are adhered by the direct wafer bonding technique to form the MIS stacked solar cell. Finally, under the standard measurement AM1.5G, the Voc can reach 720mV.