NOVELTY - A substrate (410) with a silicon surface comprising graded-density silicon to provide an antireflection surface, is positioned in a chamber. The chamber is heated to a temperature within a high-temperature processing range. With a dopant-containing precursor, an emitter junction (420) is formed proximate the silicon surface by doping the substrate. While the chamber is maintained at a temperature within the high-temperature processing range, a passivation layer is formed on the graded-density silicon anti-reflection surface.    USE - Processing of silicon surface to provide surface passivation for high-efficiency silicon-based devices e.g. silicon solar cells (all claimed). Can also be used for electronic devices, telecommunication devices, computers, and biological and medical applications.    ADVANTAGE - The method reduces optical loss of high-efficiency silicon-based devices from the silicon surface. The method economically provides solar cells having excellent light detection efficiency and energy conversion efficiency.    DETAILED DESCRIPTION - A substrate with a silicon surface comprising graded-density silicon to provide an antireflection surface, is positioned in a chamber. The chamber is heated to a temperature within a high-temperature processing range. With a dopant-containing precursor which is in communication with the chamber or that was previously formed on the silicon surface, an emitter junction is formed proximate the silicon surface by doping the substrate. While the chamber is maintained at a temperature within the high-temperature processing range, a passivation layer is formed on the graded-density silicon anti-reflection surface. INDEPENDENT CLAIMS are included for the following:    (1) formation of high-efficiency silicon-based device; and    (2) high-efficiency silicon solar cell (400).    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the solar cell fabricated with a silicon layer textured with catalytic metals.    Solar cell (400)    Substrate (410)    Emitter junction (420)    Electrical contact (430)    Back surface field layer (440)    Contact layer (450)