Understanding the effect of size scaling on resistance window in phase-change memory (PCM) requires accurate models for conduction in the amorphous phase of the active chalcogenide material. This work presents a new conduction model for the chalcogenide amorphous phase, describing Poole-Frenkel (PF) transport through localized states with distributed activation energy. The new model accounts for the scaling dependence of resistance, activation energy and current noise. Scaling perspectives for resistance window and noise amplitude at nodes F = 45 - 8 nm are finally shown.