interference using a reflection grating: how to determine the slit width?

phil02

Hello!
I'm working on a surface analysis of a silicon-microstrip-detector.
That is basically a silicon wafer with p- and n- doped strips on it. They are periodically produced on the crystal. Therefore I can use it as a diffraction grating for visible light to do my surface analysis.
My light source is a common laser pointer.

What I measure is:
- the Intensity of the Light (I) at many different angles (alpha)

What I have to know and want to calculate is:
1. the slit distance (-> the grating constant) [no problem here]
2. the slit width [big problems here]

Now my question is:
concerning 2.: Can I calculate the slit width using the interference pattern?
I'm not sure if I could do this using some kind of Fraunhofer diffraction?
I wasn't able to find any formula relating the slit width of a grating to the interference pattern it creates.

Maybe you can help me with that. Many Thanks, phil