Wath Time an Incident Wave Packet is Reflected?

We study the one dimensional time dependent Schr\"{o}dinger equation for a potential step with $E < V_0$. We obtain the wave is not instantaneously reflected, but for a few moment of time the wave packet penetrate into inaccessible classically region and then reflected. So it is shown that one can write the peneterated wave paket as superposition of incident and reflected wave packets like.