Please get a master's degree first. Accelerating from degree to doctorate is very dangerous. There is no turning back if you cannot fulfil the requirements for a PhD due to your inexperience in academia. If you just want to tick the box of getting a Dr. in front of your name,forget it

Himal,

In the US, the best Ph.D. programs, especially in the STEM fields, accept applicants who only have undergraduate degrees. Once accepted, those students can receive a Masters on their way to the Ph.D.

One exception to this is in fields where a Masters degree could be terminal, e.g., social work, computer science, engineering, mathematics, et al.

Hope this helps.

Don P.