$N$-type resonances excited in rubidium atoms confined in micrometric-thin cells with variable thickness from 1 μm to 2 mm are studied experimentally for the cases of a pure Rb atomic vapor and of a vapor with neon buffer gas. Good contrast and narrow linewidth were obtained for thicknesses as low as 30 μm. The higher amplitude and sharper profile of $N$-type resonances in the case of a buffered cell was exploited to study the splitting of the ${}^{85}\mathrm{Rb}$$D_1$$N$-resonance in a magnetic field of up to 2200 G. The results are fully consistent with the theory. The mechanism responsible for forming $N$-resonances is discussed. Possible applications are addressed.