Epitaxial Defects in Nanoscale InP Fin Structures Revealed by Wet-Chemical Etching

Abstract

In this work, we report on wet-chemical defect revealing in InP fin structures relevant for device manufacturing. Both HCl and HBr solutions were explored using bulk InP as a reference. A distinct difference in pit morphology was observed between the two acids, attributed to an anisotropy in step edge reactivity. The morphology of the etch pits in bulk InP suggests that the dislocations are oriented mainly perpendicular to the surface. By studying the influence of the acid concentration on the InP fin recess in nanoscale trenches, it was found that aqueous HCl solution was most suitable for revealing defects. Planar defects in InP fin structures grown by the aspect ratio trapping technique could be visualized as characteristic shallow grooves approximately one nanometer deep. It is challenging to reveal defects in wide-field InP fins. In these structures, dislocations also reach the surface next to stack faults or twinning planes. Due to the inclined nature, dislocation-related pits are only a few atomic layers deep. Extending the pits is limited by the high reactivity of the fin sides and the strong surface roughening during etching. The process window for revealing wet-chemical defects in InP fins is limited.

Study of the Anisotropic Wet Etching of Nanoscale Structures in Alkaline Solutions

“…This anisotropic etch can be a desired or undesired etchant property. In the former case, anisotropic etching is commonly utilized for the fabrication of MEMS [1,2] or other morphological structures like V-grooves for high aspect ratio trapping [3,4]. The continued drive in the semiconductor industry for smaller, faster and cheaper integrated circuits has driven the industry to the 7 nm technology node and beyond, and ushering in a new era of highperformance 3-dimensional transistor structures.…”

Unveiling the 3D Morphology of Epitaxial GaAs/AlGaAs Quantum Dots

“…This also explains the crossover for the main facet angles in the inset of Figure f. At a nanohole fabrication temperature of 635 °C, the presence of facets along the inner wall may result in stacking faults and enhance the etching rate. ,, The appearance of the hillock peak-B further verifies the existence of multiangle facets on the sidewall near the nanohole opening.…”

“…Selective wet etching can complement and thus compensate limitation of AFM and TEM, which can only perform two-dimensional characterization. Etch rate increases around the defect sites, such as dislocations or stacking faults, and causes etch pit formation. − In combination with AFM, the 3D alloy composition and distribution of In(Ga)As and SiGe QDs has been successfully obtained, while the composition distributions and conductance distributions of GeSi quantum rings have been detected. This method provides a fast, intuitive, and controllable way to study the QD morphology.…”

Dislocations behavior in highly mismatched III-Sb growth and their impact on the fabrication of top-down n + InAs/p + GaSb nanowire tunneling devices

“…Another more accurate method to determine TD density would be the use of chemical etching for defect revealing. 28 Figure 3 fabrication after the III-V NW etching step [see Fig. 4(a)].…”