AVS 45th International Symposium
    Electronic Materials and Processing Division Wednesday Sessions
       Session EM2-WeA

Paper EM2-WeA10
Silicon Nitride Islands as Oxidation Masks for the Formation of Silicon Nano-Pillars

Wednesday, November 4, 1998, 5:00 pm, Room 316

Session: Application of Scanning Probes to Electronic Materials
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
E.-H. Lee, ETRI, Republic of Korea
Correspondent: Click to Email
We have used nanometer-scale silicon nitride islands as oxidation masks for the formation of silicon nano-pillars. For the growth of silicon nitride islands on Si(111)-7x7 surface, two different methods were used; N @sub 2@ exposure at temperatures between 700 and 800 ° C and 100 eV N @sub 2@ @super +@ ion exposure at room temperature followed by subsequent post-annealing at 980 ° C. Scanning tunneling microscope (STM) images taken from the two differently prepared surfaces showed a submonolayer coverage of nanometer-sized silicon nitride islands. On these surfaces, O @sub 2@ was exposed at high temperatures where silicon etching was dominant over oxide formation. It was found that N @sub 2@ @super +@ ion induced silicon nitride islands work as successful oxidation masks to form silicon nano-pillars as high as several nanometers via selective oxygen etching of silicon. On the other hand, oxygen exposure to the silicon surface covered with N @sub 2@ - induced silicon nitride islands resulted in the increase of lateral size and density of pillars, compared to the initially formed islands. Such difference can be explained in terms of the segregation of extra nitrogen species which had migrated into subsurface region when N @sub 2@ had been exposed at high temperatures. Optimum conditions for the formation of silicon nano-pillars could be obtained by controlling the nitridation temperature, annealing time, and oxidation temperature. In this paper, we will propose a successful way to form silicon nano-structures using silicon nitride islands and also discuss underlying mechanisms of the island growth.