Polysilicon contact structures for silicon solar cells using atomic layer deposited oxides and nitrides as ultra‐thin dielectric interlayers
Christian Reichel, Frank Feldmann, Armin Richter, Jan Benick, Martin Hermle, Stefan W. Glunz
Abstract
Abstract Polysilicon contact structures with ultra‐thin atomic layer deposited (ALD) oxide and nitride interlayers based on SiO x , SiN x , AlO x , AlN x , and TiO x either as part of an interlayer stack when applied on top of a conventional thermally‐grown SiO x or as a single interlayer were investigated. ALD SiO x single interlayers provided a very good passivation quality with high implied open‐circuit voltage and low‐specific contact resistivity when an optimal thickness and annealing temperature was applied. Also, ALD SiN x single interlayers showed a promising passivation quality, while AlO x and AlN x interlayers only allowed for a moderate and TiO x interlayers exhibited a very poor passivation quality. ALD SiO x interlayers on planar and textured silicon solar cells with poly‐Si(p) hole‐selective contacts and poly‐Si(n) electron‐selective contacts enabled a conversion efficiency of almost 21% as a proof‐of‐concept. These results are comparable with silicon solar cells with conventional thermally‐grown SiO x , showing that ALD SiO x interlayers are an alternative to conventional thermally‐grown SiO x in polysilicon contacts structures.