No, you may not.

The description of the flaming sphere spell specifically states that:

A 5-foot-diameter sphere of fire appears in an unoccupied space of your choice within range and lasts for the duration. Any creature that ends its turn within 5 feet of the sphere must make a Dexterity saving throw. The creature takes 2d6 fire damage on a failed save, or half as much damage on a successful one.

If you ram the sphere into a creature, that creature must make the saving throw against the sphere’s damage, and the sphere stops moving this turn.

When you move the sphere, you can direct it over barriers up to 5 feet tall and jump it across pits up to 10 feet wide. The sphere ignites flammable objects not being worn or carried, and it sheds bright light in a 20-foot radius and dim light for an additional 20 feet.

This clearly speaks to the sphere’s solidity. It’s an object that has to move around obstacles, and leaps over pits (note that the spell says it jumps, not that it hovers). On top of that, it distinctly states that creatures that end their turn within 5 feet of it are affected, but does not state anything about a creature ending its turn in the sphere’s square.