Physicist are widely recruited in the R&D departments of this companies. But for that you need to have a good profile which obviously includes a good research and obviously a PhD degree. For Physics graduates, if you are from experimental background and cover your PhD then you can join as Data Analyst or Programmer or Developer at Google and other Tech companies. If you want to go for the SpaceX then having a background in Space Physics, Solar Physics, Atmospheric Physics & Astrophysics will be influential.

So yeah! you can work there, but you need to make yourself ready & mark you up as a highly skilled Physicist. Also if you wish you can do MTech course after your MSc in Optoelectronics, Solid State Electronics, Space Technology etc which can also be a influential pathway to this companies.

For more options regarding Physics as a career, visit the link below:

https://www.careers360.com/courses/physics-course

I hope this helps. Wish you a great eve!