Investigation of dominant factors to control c-axis tilt angle of aln thin films for efficient energy harvesting

We investigated the experimental conditions affecting degree of c-axis tilt angle, which is related to output power of piezoelectric energy harvesters, of the oriented aluminum nitride (AlN) thin films grown using electron cyclotron resonance (ECR) sputtering. The c-axis tilt angle of the AlN thin films deposited on silicon (100) substrates was measured by X-ray diffractometry with a 2-dimenaioanl detector (2D XRD). This study verified that 1) lowering the incident angle of the flux during thin film growth and 2) lower substrate temperature, and 3) increasing the buffer layer roughness are effective ways to increase the c-axis tilt angle of the AlN thin films.