NOVELTY - Forming a passivation anti-reflection layer on a solar cell substrate comprises: (a) flowing a first process gas mixture into a process volume within a processing chamber; (b) generating plasma in the processing chamber at a power density of greater than 0.65 W/cm2; (c) depositing a silicon nitride-containing interface sub-layer on a solar cell substrate in the process volume; (d) flowing a second process gas mixture into the process volume; and (e) depositing a silicon nitride-containing bulk sub-layer on the silicon nitride-containing interface sub-layer.    USE - The method is used for forming a passivation anti-reflection layer on a solar cell substrate (claimed).    ADVANTAGE - The passivation layer has combined functional and optical gradient properties which minimize surface recombination of the charge carriers, improve the formed solar cell efficiency, and result in a substantially pinhole free passivation layer that has desirable optical and passivating properties.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a passivation/anti-reflective coating (ARC) layer formed in a solar cell device comprising: (a) a silicon nitrogen-containing interface sub-layer disposed over one or more p-type doped regions formed in a surface of a solar cell; and (b) a silicon nitrogen-containing bulk sub-layer disposed over the silicon nitrogen-containing sub-layer, where the interface sub-layer has a refractive index greater than that of the bulk sub-layer and both the interface sub-layer and the bulk sub-layer have an extinction coefficient of 0-0.1;    (2) a method for detecting pin-holes formed in a passivation layer on a solar cell;    (3) a solar cell comprising: (a) a substrate having a junction region; and (b) a passivation anti-reflection layer on a surface of the substrate; and    (4) a system for forming a film on a solar cell comprising: (a) a plasma processing chamber for forming a passivation/ARC layer on a solar cell substrate within a processing volume of the processing chamber; and (b) a system controller in communication with the plasma processing chamber, where the system controller is configured to control the plasma power density, the first process gas mixture flow rates, and the second process gas mixture flow rates so that the interface sub-layer has a refractive index greater than that of the resulting bulk sub-layer and both the interface sub-layer and the bulk sub-layer have an extinction coefficient of 0-0.1.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a portion of a substrate.    Base region (101)    N-doped emitter region (102)    P-n junction region (103)    Top surface (105)    Bottom surface (106)    Passivation or anti-reflective coating layer (120)    Interlace sub-layer (121)    Bulk sub-layer (122)