I recently finished my PhD and got a 6 month internship at a Startup, I'm one of the engineers and the other person currently working is the general manager.

The company has 6 founders, who are on the board and aren't involved in the day to day activities. I have been liking the work, the schedule and the challenges I'm facing right now. I have been told that they would like to keep me on after the 6 month internship. We have decent finding for a future R&D project and looks like we will be making sales in the next 8-10 months.

I have no idea, how I would negotiate a salary here. Do I ask for equity+Salary Or do I just ask for a market rate salary ? In what cases does equity make sense ?