AVS 46th International Symposium
    Electronic Materials and Processing Division Wednesday Sessions
       Session EM-WeP

Paper EM-WeP9
Silicon Nano-dots Fabricated on a Si(100) Surface via Thermal Nitridation and Oxygen Etching Reactions

Wednesday, October 27, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: J.S. Ha, ETRI, Republic of Korea
Authors: J.S. Ha, ETRI, Republic of Korea
K.-H. Park, ETRI, Republic of Korea
W.S. Yun, ETRI, Republic of Korea
Correspondent: Click to Email
We have fabricated silicon nano-dots with a very uniform size distribution on a Si(100) surface via a thermal nitridation followed by an oxygen etching reaction. Nitrogen gas was exposed to a clean Si(100) surface at 800 @super o@C and this surface was subsequently reacted with O@sub 2@ gas at 700 @super o@C under an oxygen partial pressure of 1x10@super -7@ Torr. Scanning tunneling microscope (STM) measurement of the surface morphology showed that silicon nano-dots with an average size of 5 nm were formed as a result of selective oxygen etching of silicon surface. It is considered that nanometer-scale silicon nitride islands worked successfully as masks for the oxygen exposure at high temperatures. The number density of silicon nano-dots is estimated to be 1 x 10@super 12@ / cm@super 2@. Reduction of the nitridation temperature to 700 @super o@C resulted in the similar surface features with a little bit smaller sizes, indicating that silicon nitride islands formed even at this temperature can be successfully used as masks for oxygen exposure. Further investigation of the post-annealing effect on the resultant surface morphology showed that the coalescence of small sized silicon nitride islands into larger ones, which was clearly observed in the case of Si(111) surface, was not noticeable on the Si(100) surface. Therefore, uniform and small size distribution of Si nano-dots could be obtained on the Si(100) surface. In this paper, we will also discuss on the underlying reaction mechanisms based upon experimental results. This study suggests a simple but efficient fabrication method of silicon nano-dots using gas-surface reactions on the silicon surface in an ultra-high vacuum system.