As correctly said by Arun, no amount of Background check is going to help as u can sue your company if it divulges your salary.. But then the ways you can get caught are:
1. Companies ask for your pay-slips..
2. If u by hook or by crook, can arrange fake pay-slips, then you will get caught while furnishing Form 16B.
3. If u have still managed to get away without any harm, the problem is everyone has a rough idea at what designation what payscales are offered in that particular company.. So, you will definitely invite raised eyebrows.. Not a good thing at all. Might need to do a lot of justification to the HR folks.
4. If you can still convince them, you are a genius.
What is stopping you from faking even work-experience and your degree. You can easily bag a post of Project Lead or Manager by showing extra work-ex
All said and done, Manipulating your salary details do not have much impact. The reason being most companies have slabs for particular roles. So no matter what u show in your prior salary they won't pay u outside this slab..
Besides, whatever leverage of a few thousands you get by faking salary slips, you can easily get otherwise by remarking that I need extra benefits to be sure about the jump.. Or I am not a job-hopper and hence I need extra premium to jump the ship so that I can commit to XXX for a longer time.. It will go down with the authorities in concern better than a fake slip...