The main thing is in the switch - if you configure the switch port as a layer 3 interface with an IP address and the routers - effectivly you have created a pt-pt link on the IP subnet.
No other switch port can take part in the broadcast domain.
If you create an SVI in a vlan and give the SVI an IP address, then any port configured in the switch and anyother switch connected via a trunk port will be able to participate in the broadcast domain.
HTH>