Topographical and electrical study of contact and intermittent contact mode InP AFMlithography

Abstract

In order to fabricate nanoscale oxide patterns on an InP(001) surface, local anodizationby atomic force microscopy (AFM) contact and intermittent contact modes hasbeen performed. Contact mode results are similar to those obtained with thelocal anodization of silicon, and mainly limited by the effect of space charge thatoccurs during the oxide growth. The existence of this space charge associatedwith the poor dielectric quality of the obtained oxide has been verified byperforming scanning capacitance microscopy (SCM) measurements. Results foroxidation using intermittent AFM contact mode associated with a modulatedvoltage are more specific. For a more than two decade variation of probe velocity(0.01–5 µm s−1), the AFM oxidation introduces no significant changes in the oxide pattern. Experimentson the influence of oxidation time give rise to two regimes. First, for times shorter than100 ms, a high growth rate is found. Second, for oxidation times longer than 100 ms, weobserve an oxide height saturation and a significant decrease of lateral growth rate. Theseresults provide a way to easily control the oxide shape. The space charge neutralization inthis mode has also been investigated by SCM. The interesting results for intermittentcontact oxidation confirm the capability of this technique to modify a nanoscale InPsurface.