Structural evolution of the low energy deuterium-implanted silicon

Abstract

Structural changes of (111)Si after 10keV D⁺ ₂ ion implantation with fluence in the range of 10¹⁶ – 10¹⁹ cm⁻² at room temperature have been studied with cross-sectional transmission electron microscopy (XTEM), secondary ion mass spectroscopy (SIMS) and neutral molecules mass spectroscopy (NMMS).

Three stages of structural, as well as chemical evolution is observed. For fluence less than (3–4) · 10¹⁶cm⁻² deuterium retains in the target through trapping on the dangling bonds with SiD-complexes formation. This process results in formation of the strongly damaged region. As the fluence is increased the buried amorphous layer on the depth close to R_d appears. Simultaneously generating of SiD₂-complexes begins. The nucleation and incorporation of SiD₂-complexes leads to a network of voids creation. For fluence higher than 10¹⁸ cm⁻² the erosional relief at the target surface is formed due to effective sputtering of the amorphous material with voids.

Key Words:

• implantation
• silicon
• deuterium
• XTEM
• amorphization
• voids