Passivation of Liquid‐Phase Crystallized Silicon With PECVD‐SiNx and PECVD‐SiNx/SiOx

• Published in: Physica status solidi. A, Applications and materials science Vol. 215; no. 14
• Main Authors: Preissler, Natalie, Amkreutz, Daniel, Dulanto, Jorge, Töfflinger, Jan Amaru, Trinh, Cham Thi, Trahms, Martina, Abou‐Ras, Daniel, Kirmse, Holm, Weingärtner, Roland, Rech, Bernd, Schlatmann, Rutger
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 24.07.2018
• Subjects: Absorption cross sections; Charge density; Charge transfer; Chemical vapor deposition; Crystallization; Electrical measurement; Electron energy; Electron energy loss spectroscopy; Energy transmission; interface passivation; liquid‐phase crystallized silicon; MIS (semiconductors); Order parameters; Organic chemistry; Oxidation; Passivity; plasma‐enhanced chemical vapor deposition; Silicon nitride; silicon oxide; Silicon oxides; Silicon oxynitride; Transmission electron microscopy
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201800239

Silicon nitride (SiNx) and silicon oxide (SiOx) grown with plasma‐enhanced chemical vapor deposition are used to passivate the front‐side of liquid‐phase crystallized silicon (LPC‐Si). The dielectric layer/LPC‐Si interface is smooth and layers are well‐defined as demonstrated with transmission electron microscopy. Using electron energy loss spectroscopy a thin silicon oxynitride is detected which is related to oxidation of the SiNx prior to the silicon deposition. The interface defect state density (Dit) and the effective fixed charge density (QIL,eff) are obtained from high‐frequency capacitance‐voltage measurements on developed metal‐insulator‐semiconductor structures based on SiOx/SiNx/LPC‐Si and SiOx/SiNx/SiOx/LPC‐Si sequences. Charge transfer across the SiNx/LPC‐Si interface is observed which does not occur with the thin SiOx between SiNx and LPC‐Si. The SiOx/SiNx/LPC‐Si interface is characterized by QIL,eff > 1012 cm−2 and Dit,MG>1012 eV−1 cm−2. With SiOx/SiNx/SiOx stack, both parameters are around one order of magnitude lower. Based on obtained QIL,eff and Dit(E) and capture cross sections for electrons and holes of σn = 10−14 cm s−1 and σp = 10−16 cm s−1, respectively, a front‐side surface recombination velocity in the range of 10 cm s−1 at both interfaces is determined using the extended Shockley‐Read‐Hall recombination model. Results indicate that field‐effect passivation is strong, especially with SiOx/SiNx stack. Liquid‐phase crystallized silicon is passivated using silicon nitride or a silicon nitride/silicon oxide stack prepared with plasma‐enhanced chemical vapor deposition. The origin of the passivation quality is examined through the determination of the defect state density and the fixed charge density with capacitance‐voltage measurements on developed metal‐insulator‐semiconductor structures. The surface recombination velocity is calculated using the Shockley‐Read‐Hall formalism.