Eliminating the surface inversion layer under the field oxide by low pressure rapid thermal annealing
Journal
Journal of the Electrochemical Society
Journal Volume
141
Journal Issue
9
Pages
2498-2502
Date Issued
1994
Author(s)
Abstract
A rapid thermal anneal (RTA) at low pressure is proposed as an efficient method for the elimination of the surface inversion layer formed by the charges within the field oxide orby the leakage current along the field oxide surface which is easily contaminated byphotoresist, water molecules, and mobile ions. From the high-low frequency C-V measurements, it was found that a 900 ~ RTA at a pressure of 300 Torr can remove the field oxide surface contaminants sufficiently and make the distorted portion in the strong inversion region of the high frequency C-V curve return to normal. The practice of rapid thermal annealing after chemical etching and cleaning can prevent he field oxide surface from contamination caused by the subsequent high temperature process. It was also found that after a low pressure RTA the gate oxide endurance can be dramatically enhanced and is comparable to that of the conventional furnace-annealed gate oxide. Rap id thermal anneal (RTA) has been used for semicon-ductor device fabrication due to its fast heating nature wh ich can avoid the possible dopant redistribution during the high temperature processing cycle. Because of its abil-ity to reduce the native oxides and chemical oxides, RTA has also been applied to the cleaning of the silicon surface
Type
journal article