ETCHING STUDIES OF DIFFUSION SOURCE BORON GLASS

For selective boron doping of silicon, a SiO//2 diffusion mask is used. In many cases, it is advantageous to retain the same SiO//2 mask on the silicon slice after diffusion and remove the boron diffusion source glass. To accomplish retention of the SiO//2 mask while dissolving boron diffusion source glass, a selective etch is required that favors dissolution of boron-doped glass. Etching solutions that fulfill this need have been found.