Nanoscale wafer patterning using SPM induced local anodic oxidation in InP substrates

Atomic force microscopy (AFM) assisted local anodic oxidation (LAO) offers advantages over other semiconductor fabrication techniques as it is a low contamination method. We demonstrate the fabrication of deep and highly reproducible nanohole arrays on InP using LAO. Nanohole and nano-oxide mound radius and depth are controlled independently by altering AFM tip bias and humidity, with a maximum nanohole depth of 15.6 +/- 1.2 nm being achieved. Additionally, the effect of tip write speed on oxide line formation is compared for n-type, p-type and semi-insulating substrates, which shows that n-type InP oxidizes at a slower rate that semi-insulated or p-type InP. Finally, we calculate the activation energy for LAO of semi-insulating InP to be 0.4 eV, suggesting the oxidation mechanism is similar to that which occurs during plasma oxidation.

Automated summary

Atomic force microscopy (AFM) assisted local anodic oxidation (LAO) is a low contamination method for semiconductor fabrication. In this study, we demonstrate the fabrication of deep and highly reproducible nanohole arrays on InP using LAO. The size and depth of the nanoholes and nano-oxide mounds can be controlled independently by altering AFM tip bias and humidity. The oxidation mechanism of semi-insulating InP during LAO is found to be similar to that of plasma oxidation.