Fabrication of BESOI-materials using implanted nitrogen as an effective etch stop barrier

Summary form only given. Silicon sensors with membrane structures or fabrication of bonding and etch-back silicon-on-insulator (BESOI) materials are commonly produced using p⁺-doped silicon as an effective etch stop in EDP or KOH solutions. It is shown that an implanted dose of nitrogen (¹⁴N⁺) in the silicon can also act as an effective etch barrier in EDP solutions. The results show that a dose of 4×10¹⁶ cm^-2 at 120 keV is enough to drastically decrease the silicon etch rate, from 1.4 μm/min to practically zero. There are two major advantages to the use of implanted nitrogen as an etch stop. Since the diffusion constant for nitrogen in silicon (at this concentration) is very low as compared to the diffusion of boron and phosphorus, it is easier to get a well-defined thickness if the following process steps includes high-temperature steps. Also, the nitrogen is not an effective electrically active dopant