Low cost spray-coating boron diffusion on n-type silicon

Abstract

A low cost spray-coating technique is implemented to study the boron diffusion in n-type silicon wafers. Temperature and diffusion time have been the main factors on the resulting sheet resistance (Rsheet), reaching the highest values at high temperatures and diffusion times due to the formation of a thick borosilicate glass layer on the wafer surface. This layer has been etched off by HF dipping resulting on more doped emitters. Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) measurements have been carried out in order to analyze the correlation of Rsheet with the amount of sprayed precursor.