MA in one subject and PhD in another

I came back to school after working for two years. My degree was in economics but I wanted to come back for philosophy (I really enjoyed my two logic courses during undergrad). I spent three non-degree semesters catching up in philosophy (and raising my grades). I was fortunate enough to get into a very solid MA program and will be attending next fall–I’m very excited.

Here’s the problem–in my third semester I took a second course in semantic theory (through the department of linguistics), and absolutely loved it. Whereas doing philosophy seems, well, lateral, when doing semantics I have some sense of purpose, some sense that I am progressing towards something; it A) has a scientific element, to the extent that we treat linguistic intuitions almost as observed date (to then be reverse engineered into our formal system) and B) has real-world applications, like helping google improve their natural language algorithms (to interpret searches). In other words, I really want to do semantics.

If I count my two logic courses, my course in the philosophy of language, my extra course in semantics, and another half-course at the MA level, I’ll have a total of 5 full linguistics courses by the time I finish my MA (my undergrad minor was in linguistics). Would this be adequate preparation to be admitted to a PhD program in linguistics? Alternatively, how flexible would a philosophy department be to semantics being my focus for a PhD?

Any suggestions would be great!