Method to Improve the Controllability of Lightly Doped Drain SiO(2) Spacer Formation
Original Publication Date: 1981-Jul-01
Included in the Prior Art Database: 2005-Feb-12
One of the problems encountered in the formation of lightly doped drain (LDD) silicon dioxide (Si0(2)) spacers in a double polysilicon random-access memory (RAM) is the thinning of the field silicon dioxide layer and the source/drain screen silicon dioxide during the latter part of spacer etching operation. This results in a reduction of the thick silicon dioxide threshold and introduces uncertainties to the projected ion range of the source/drain ion implantation.