In this work, the plasma-enhanced atomic layer deposition (PE-ALD) technique, including continuous hydrogen plasma, was studied for GaN growth. Also, the use of plasma at the nitrogen step only as well as argon plasma surface  activation were explored. The structural properties of GaN layers grown on Si substrates at different conditions were studied by atomic force microscopy (AFM). It was shown that in-situ Ar plasma treatment during the PE-ALD process of GaN growth leads to improvement of the surface roughness as well as an increase in growth rate. On the contrary, the use of hydrogen plasma during the process leads to a drastic increase in surface roughness due to  parasitic deposition.