Effect of 80-keV Ne+ ion implantation on acoustic surface wave attenuation in LiNbO3

Abstract

Acoustic surface wave attenuation in LiNbO₃ caused by ion implantation was studied as a function of fluence and surface wave frequency. 80‐keV Ne⁺ ions were implanted at five fluences covering the range 10¹⁴–10¹⁶ ions/cm². The yz Rayleigh surface waves were generated spanning the interval 100–1000 MHz by interdigital transducers operating at odd harmonics. Attenuation was measured directly by a standard laser probe using reflected light. At low acoustic power densities, the data can be fit by P(z)/P₀=10−Af²z, where P is acoustic power, f is the surface wave frequency, and A is a constant for each fluence used. The values of A show a definite peak with fluence at around 10¹⁵ ions/cm², where A=9 × 10⁻⁵ dB cm⁻¹ MHz⁻²±10%. This is about twenty times the value of A for an unimplanted surface.