Traceability matrix that we create depends on test methods
that we follow

In my company it is like a mapping beween the test cases
written from FSD and BRD's 

we create a 1*1 matrix between the list of points ponited in
FSD/BRD and the test cases written by us,that's it.

RTM :
This is done to map Requirements along with Test 
cases.Before executing Test Cases it's necessary to do RTM.

Example :
Unique No|Requirements|Source of 
Requirements|SRS/Functional Doc.|Design Spec.|Program 
Mod|Test Case|Changes|Remarks

(this are the parts of RTM specified in Test Approach 
Document)