TECHNOLOGY FOCUS - ELECTRONICS - Preferred Method: In passivating at least a part of a surface of a semiconductor substrate, the density of the a-Si:H layer precursor is at each injection nozzle (19) is lower than 1x1023 particles/m3, for example about 6x1022 particles/m3 or lower. The total flow rate of the precursor, being injected, is higher than 1 sccs, for example 10 sccs or higher. The flow rate of the precursor through each nozzle (19) is lower than 1.25 sccs, for example lower than 0.7 sccs. The precursor is a silane. The precursor is monosilane (SiH4). The precursor is a SiN:H layer. The lateral distance (R) between a center line of the plasma and each injection nozzle (19) is larger than 4 cm. The longitudinal distance (L2), measured in parallel with the center line of the plasma, between each nozzle (19) and the plasma source (3) is in the range of 2-10 cm, more particularly 4-6 cm. The injector device (17) is ring shaped. The injector device (17) is provided with an aperture (18), the plasma passing through the aperture, a diameter of the aperture being larger than 8 cm, for example about 10 cm or larger. The total, cumulative, injection surface defined by the number of injection nozzles is larger than 7 mm2. The total, cumulative, injection surface defined by the number of injection nozzles is larger than 12 mm2. The precursor is injected into the plasma from more than 8 separate injection openings (19), for example more than 15 openings (19). The openings (19) are arranged symmetrically, at equally spaced intervals with respect to the plasma, with respect to a plasma center line. The pressure in the process chamber is lower than 0.2 mbar. The pressure in the process chamber is lower than 0.1 mbar. The pressure in the process chamber is in the range of 0.05-0.1 mbar. The substrate treatment temperature is in the range of 150 degrees C, for example the range of 175-400 degrees C. The growth rate of the passivation layer is larger than 1 nm/second. Hydrogen is supplied to the plasma via the plasma source. The plasma is argon plasma. The thickness of the passivation layer realized on the substrate (1) by the plasma treatment process is in the range of 1-1000 nm. The thickness of the passivation layer realized on the substrate (1) by the plasma treatment process is in the range of 50-150 nm, for example 60-100 nm. The thickness of the passivation layer realized on the substrate (1) by the plasma treatment process is in the range of 1-20 nm, for example 1-10 nm. The at least one plasma source comprises at least one plasma cascade source (3). It comprises depositing at least one second layer after realizing the passivation layer, preferably successively by the same apparatus. It also comprises: placing the substrate (1) in a process chamber (5); maintaining the pressure in the process chamber (5) at a vacuum pressure; maintaining the substrate (1) at a substrate treatment temperature suitable for realizing the layer; generating a plasma (P) by at least one plasma source (3) mounted on the process chamber (5) at a distance (L) from the substrate surface, at least part of the plasma (P) being injected into the chamber (5) and achieving a supersonic speed; contacting at least a part of the plasma (P), injected into the chamber (5), with the part of the substrate surface; and supplying at least one precursor suitable for a-Si:H passivation layer realization to the part of the plasma (P); where the pressure in the process chamber is lower than 0.1 mbar. It also comprises: placing the substrate (1) in a process chamber (5); maintaining the pressure in the process chamber (5) at a vacuum pressure; maintaining the substrate (1) at a substrate treatment temperature suitable for realizing the layer; generating a plasma (P) by at least one plasma source (3) mounted on the process chamber (5) at a distance (L) from the substrate surface, at least part of the plasma (P) being injected into the chamber (5) and achieving a supersonic speed; contacting at least a part of the plasma (P), injected into the chamber (5), with the part of the substrate surface; and supplying at least one precursor suitable for a-Si:H passivation layer realization to the part of the plasma (P); where the precursor is injected into the chamber via a number of injection nozzles, a lateral distance (R) between a center line of the plasma and each injection nozzle being larger than 4 cm. Preferred Apparatus: The apparatus comprises: a process chamber (5), having a substrate holder for holding a substrate; at least one remote plasma source (3) mounted on the process chamber (5) at a distance from the substrate holder, for generating a plasma that expands into the chamber (5); an injector device for supplying at least one precursor suitable for layer realization to the expanding plasma (P); where the injector device is provided a number of nozzles, a total, cumulative, injection surface defined by the number of injection nozzles being larger than 10 mm2.