High quality tunneling oxides for passivated contacts and heterojunctions for high efficiency silicon solar cells

Abstract

We analyze the chemical passivation quality of silicon oxide-nanolayers on crystalline silicon wafers prepared by different oxidation methods with surface photo voltage and quasisteady-state photo conductance measurements. It is shown that for wet chemical oxidation and plasma oxidation, adequate passivation of the interface defects is achieved by subsequent anneal in forming gas environment. Furthermore, we present a simple oxidation method by means of rapid thermal oxidation, which requires no complex surface pre-treatment or surface preconditioning after cleaning. By rapid thermal oxidation (RTO) in a gaseous mixture of argon and oxygen and subsequent anneal in forming gas, a reproducible preparation method of high-quality ultra-thin oxide-nanolayers with a nearly intrinsic energetic distribution of interface states and a defect density of states of only 1 x 10 12 cm -2 eV -1 at the minimum of the distribution is demonstrated.

Dual-Function Electron-Conductive, Hole-Blocking Titanium Nitride Contacts for Efficient Silicon Solar Cells

“…Generally, an ultrathin silicon oxide (1-2 nm) formed on silicon surfaces can reduce the D it to the order of 10 12 cm À2 .eV À1 . 34,35 We found that the electron barrier height decreases to 0.29 eV with a D it of 7 3 10 12 cm À2 .eV À1 . This result is consistent with the phenomenon we observed (as shown in Figure 2) where inserting thin SiO 2 reduces the r c at the TiN/SiO 2 /n-Si interface.…”

IMPROVEMENT OF THE PASSIVATION PROPERTIES OF SiO₂ FILMS, GROWN BY THE METHOD OF RAPID THERMAL ANNEALING, AFTER CHEMICAL RCA TREATMENT

“…K.M. Gad и соавторы в работе [8] сравнили пассивирующие свойства пленок SiO 2 , выращенных различными методами. Как показали результаты, ультратонкие пленки диоксида кремния, синтезированные методом быстрого термического отжига, показали наилучшие свойства, в особенности после отжига в формирующем газе N 2 (95%) + Н 2 (5%) при температуре 400 о С в течение 20 минут.…”

Two-Dimensional Functionalized Ultrathin Semi-Insulating CaF2 Layer on the Si(100) Surface at a Low Temperature for Molecular Electronic Decoupling

“…This topic has thus been the object of a large amount of fundamental 2 and applied investigations 3 . It is still impacting various research fields targeting both applied and fundamental physics in which flexible opto-electronic devices 4,5,6 , sensors 7,8 or biological functions are still feeding new paradigms 9,10 .…”