A2.3 High-Temperature Acoustic Loss in Bulk AlN Piezoelectric Resonators
- SMSI 2020
(did not take place because of Covid-19 virus pandemic)
- SMSI 2020 - Sensors and Instrumentation
- A2 Piezoelectric High-temperature Sensors
- H. Fritze, I. Kogut - Clausthal University of Technology, Goslar (Germany), I. Gamov, K. Irmscher, M. Bickermann - Leibniz-Institut für Kristallzüchtung, Berlin (Germany)
- 53 - 54
Aluminum nitride (AlN) single crystals are grown by physical vapor transport under varying conditions to achieve samples that exhibit a wide range of doping concentrations for carbon, oxygen and silicon. Accordingly, properties such as electrical conductivity and acoustic loss vary significantly. Beside structural quality and essential point defects, the electrical conductivity, thermal expansion, elastic constants and acoustic losses are determined up to 900°C. Special attention is paid to the correlation of acoustic losses and electrical conductivity, as they are crucial application-relevant parameters. For example, the losses in crystals with low dopant concentration ratios of oxygen to carbon ([O]/[C] ≤ 1) are found to be determined by the electrical conductivity above about 650°C. The lowest overall losses are observed in AlN with lowest concentration of oxygen impurities.