Fabrication and characterization of porous silicon layer prepared by photo-electrochemical etching in CH3OH:HF solution

Porous silicon (PS) has been fabricated by Photo-electrochemical etching. Porous silicon was anodized on n-type Si in light using a current density of 20mA/cm2 for 10 min. The porous structure formation was confirmed using XRD and AFM studies. The root mean square (RMS) roughness of the Porous silicon layer is found to be around 47.5 nm and the ten point height was 317 nm. The average of pores diameter was 419.98nm, and the grain growth is columnar with a (211) preferred orientation. The grain size of the PS was estimated from the Scherer's formula and found to be 73 nm. All the properties of the porous silicon layer, such as porosity and the thickness depend on the anodization parameters. The porosity (P) was approximately 77 %. The thickness of the layer formed during an anodization in constant current was 3.54nm in gravimetric method, while its value was 1.77nm by using the theoretical relation.