It is highly recommended that the graduate student consider the question of financial support when selecting a dissertation topic, though the doctoral committee must not take this factor into consideration when deciding whether or not to award candidacy to the student. Life is easier for a student who can be paid as a research assistant to undertake the project proposed for the PhD. This can only happen if a student chooses a dissertation topic that meshes with the scientific goals of a faculty member. It is possible for a student to work on one project for a dissertation and another project as a paid research assistant, but such a student must expect to make slower progress towards the PhD.
There is no fixed format for the dissertation proposal. Its contents and breadth should be discussed with the chair of the doctoral committee. The student needs to provide written and oral documentation to the committee -
The committee may recommended that the student write a review of the current state of the field as part of the dissertation proposal; this review may then become the basis of the introductory chapter of the dissertation.