I have used spin-on dopants for boron diffusion in my doctoral thesis. AlliedSignal's B-150 (Allied-Signal, Milpitas, CA) formulation of borazole polymer worked well for creating etch-stopped membranes of silicon about 3.5 micron thick in EDP "F" solution. The exact results you get will depend on your furnace conditions. I simulated the results with SUPREM by assuming that the concentration of boron was at the solid solubility limit on the surface at all times, and got good match between simulation and actuals based on a 7*10^19 boron atom per cubic centimeter requirement for etch survival. The exact conditions I used were as follows: Spin B-150 at 3000 rpm for 30 seconds Furnace ramp up from 850 degrees C to 1200 degrees C over 40 minutes in 4 liter/min N2 and 100 cc/min O2 (3-inch wafers were used). Hold at 1200 degrees C for 40 minutes. Ramp down to 850 degrees C over 60 minutes in 4 liter/min O2 My furnace conditions were limited by my furnace and may not be optimal. There is a further issue you should be aware of, which is that the doping process leaves a surface film of high-boron concentration glass that etches VERY slowly in 10:1 BHF. It is much faster in 49% HF (about one minute). Further information can be found in my thesis: "Development of a Mass Producible Lipid Bilayer Support Device" by Thor Dane Osborn. University of Washington (Seattle, WA) 1994. I hope this is of some help to you. Thor Osborn ---------- >>>From: Sonbol Massoud-Ansari >>>To: MEMS@ISI.EDU >>>Subject: boron diffusion >>>Date: Monday, December 09, 1996 9:12AM >>> >>> >>>Dear MEMS researchers, >>> >>>I am trying to find some information about spin-on sources for deep boron >>>diffusion (to be used as an etch stop for EDP etching). >>> >>>I would appreciate any information on commercial vendors & manufacturers for >>>the spin-on boron sources. In addition, if any one has any experience with >>>using spin-on sources for deep boron diffusion, I would appreciate >>>any information on the quality, performance, profile etc. >>> >>>In addition, I need to locate companies/labs that can do deep boron >>>diffusion, using either liquid sources or spin-on sources, as a >>>commerical service. >>> >>>Thank you, >>> >>> -Sonbol Massoud-Ansari >>> >>> >>>