Transmission electron microscopy study of Au/ZrB2/Ag(Te) contacts to GaSb

By means of cross-sectional transmission electron microscopy (TEM) the influence of the annealing temperature on the morphology of Au/ZrB2/Ag(Te) ohmic contacts to (1 0 0)-oriented tellurium-doped GaSb substrates has been investigated. Both the shape and the size of the Ag(Te) grains significantly varied with the annealing temperature. In the sample annealed at 250 °C, below the Ag(Te)/GaSb interface, dissolution pits (DPs) were formed. At the higher annealing temperatures the DP’s were not found. After annealing at 300 °C, changes in the Ag(Te) grains located close to the interface can be seen. These changes were not observed in the sample annealed at 350 °C. In all samples the annealing caused the formation of microtwins.