Effect of the SiO2 interlayer properties with solid-source hydrogenation on passivated contact performance and surface passivation. (September 2017)

• Record Type: Journal Article
• Authors: Nemeth, Bill; Harvey, Steven P.; Li, Jian V.; Young, David L.; Upadhyaya, Ajay; LaSalvia, Vincenzo; Lee, Benjamin G.; Page, Matthew R.; Stradins, Paul
• Is Part Of: Energy procedia. Volume 124(2017)
• Page Start: 295
• Page End: 301
• Publication Date: 2017-09
• Subjects: silicon -- passivation -- passivated contact -- polysilicon -- Al2O3; Power resources -- Congresses; Power resources -- Periodicals; Power resources; Conference proceedings; Periodicals; 333.7905
• DOI: 10.1016/j.egypro.2017.09.302
• Languages: English
• ISSNs: 1876-6102

Abstract

Abstract: We investigate how SiOx oxide interlayers prepared by different techniques (chemical, thermal) in combination with hydrogen released from an ALD Al2 O3 source layer govern passivation in 1) passivated contacts based on doped poly-Si layers and tunneling SiO2, and 2) wafer surface passivation by Al2 O3 . Profiles of O and H in these structures with engineered, buried SiOx interlayers were measured by Time-of-Flight SIMS (TOF-SIMS) at nanometer resolution. Passivated contacts perform best with thermally oxidized SiOx, while chemical SiOx causes poly-Si film blistering and performance degradation. ALD Al2 O3 acts as passivating H source, significantly improving B-doped and intrinsic poly-Si contacts for IBC cells. Fast-diffusing hydrogen from the Al2 O3 source layer appears to penetrate Si wafer thickness, improving the passivation of structures at the opposite side. In contrast to the passivated contacts, chemical SiOx interlayer promotes wafer surface passivation by ALD Al2 O3, while similarly thin thermal SiO2 suppresses passivation and built-in charge.