Hi Vali, yes obviously you can have a plenty of options in this regard; like, surface modification, tunability in band gaps, absorption enhancement, etc. You can download our paper which might be quite helpful to you for better understanding.

http://www.sciencedirect.com/science/article/pii/S0925838813003393

We used FIB and SEM illumination of GaAs to pinpoint the positions where InGaAs quantum dots would preferentially nucleate. We achieved nice regular arrays. Details here:  H. Zhang and T. Walther: Controlled quantum dot formation on focused ion beam patterned GaAs substrates. In: FIB Nanostructures – Springer Lecture Notes in Nanoscale Science and Technology (Ed. Z.M. Wang) volume 20 (2013) chapter 11, pages 299-314, ISBN: 978-3-319-02873-6, DOI: 10.1007/978-3-319-02873-3 

Thanks all.

I have never seen that wafers are irradiated with electron beam before fabrication or processing. But electron beam irradiation is accomplished after finishing the fabrication of the power diodes and thyristors to reduce their minotity carrier liftetime for fast reverse recovery.

It is so that if you radiate the waferds with electrons to generate crysatllograohic defects and then undetake any high temperature processing most of the defects will be annihilated.

But a general answer is that you can irradiate wafers whenever you want to produce defects or electron beam induced current. if the wafer is treated thermally at high temperature after that the defects will be partly or completely eliminated.

Best wishes

Dear Abdelhalim, you are right in that electron and ion beams are traditionally used for patterning photoresists. Here, like the group by Rob Hull, we used it to directly pattern semicoductor surfaces and in a way this process may be regarded more like local ion implantation.