Growth and surface characterization of piezoelectric AlN thin films on silicon (100) and (110) substrates

Abstract

This work investigates the fundamental growth of c-axis oriented piezoelectric AlN thin films by RF reactive sputtering on p-type (100) and (110) silicon substrates. Substrates are treated with a 1% HF solution before deposition to remove the native oxide followed by back-sputtering using argon ions. X-ray diffraction shows a (0001) oriented columnar texture of AlN grains which is the preferred orientation for piezoelectric applications. TEM shows the presence of a 4 nm thick semi-crystalline interface between silicon and the AlN layer. A basic growth mechanism is proposed from microstructural observations.