NOVELTY - Manufacturing (M1) semiconductor layer involves depositing Group IIIA element and Group VIA element on substrate or on optional layer that is optionally disposed on the substrate; depositing Group IB element and the group VIA element on the substrate or on the optional layer, where portion of the Group IB element combines with the Group VIA element; monitoring first deposition state; and terminating or attenuating the depositing step at first critical control point based on function of the first several measurements of the indicia of the first deposition state.    USE - For manufacturing semiconductor layer photovoltaic module (claimed) for use in solar cells.    ADVANTAGE - The method ensures the production quality of films used in solar cells.    DETAILED DESCRIPTION - Manufacturing (M1) semiconductor layer involves depositing, during a first period of time, Group IIIA element and Group VIA element on a substrate or on an optional layer that is optionally disposed on the substrate; depositing, during a second period of time, Group IB element and the group VIA element on the substrate or on the optional layer that is optionally disposed on the substrate, where at least a portion of the Group IB element combines with the Group VIA element to form a (IB)2VIA composition; monitoring a first deposition state, during the depositing step, by making a first several measurements of an indicia of the first deposition state; and terminating or attenuating the depositing step at a first critical control point based on a function of the first several measurements of the indicia of the first deposition state. INDEPENDENT CLAIMS are included for the following:    (1) system for monitoring and controlling a deposition process, comprising depositor for depositing at least three elements on a substrate or an optional layer disposed on the substrate, where the deposition of one of the three elements is controlled by the depositor, where the three elements comprises Group IIIA element and Group VIA element; a monitoring unit for retrieving several measurements of indicia reflecting a deposition state of at least one of the three elements, where the monitoring unit is configured to compute a first derivative or a second derivative, with respect to time, of all or a portion of the several measurements; and a controlling unit for adjusting the deposition of one of the three elements based on a result computed by the monitoring unit; and    (2) photovoltaic module comprising substrate; and several solar cells linearly arranged on the substrate, the several solar cells comprising a first solar cell and a second solar cell, each solar cell comprising a back-electrode disposed on the substrate; a semiconductor junction layer disposed on the back-electrode; and a transparent conductive layer disposed on the semiconductor junction, where the transparent conductive layer of the first solar cell in the several solar cells is in serial electrical communication with the back-electrode of the second solar cell in the several solar cells, and where a layer of the semiconductor junction layer is constructed by the method (M1).