Depends on your specialty. For example, I am a physician assistant. We are required to have a Master's degree to practice. Some programs are offering doctorate degrees now. Will that degree get you more pay than me? No.
A doctorate does not equal an increased salary. If your career choice required a doctorate to be hired, then all the other employees have their doctorate and there is no one on a lower scale. Does that make sense?
It may get you a job and may even get you a raise, but a doctorate doesn't equal increased pay.