For EBS, there are notes on https://support.oracle.com You *must* follow those instructions. They also include the specific tools to use -- EBS comes with it's own cloning scripts as tools.
Hemant K Chitale
You cannot use RMAN to clone the Apps tier of the EBS and you may use RMAN only on the DB tier. For a complete backup, as mentioned by Hemant K Chitale, you will have to use the rapid clone utility.
To perform a rapid clone using RMAN there are plenty of step by step instructions in google which may guide in addition to support.oracle.com, Let me google that for you