High voltage diffusion along Z- and X-axes on quartz crystal

Quartz resonator quality is improved using sweeping treatment. It is well known that this operation is usually performed by applying a high electric field along the optical axis (Z) of the quartz lattice. This is due to the existence of channels formed by helicoidal structure of quartz crystal. This crystallographic structure exhibits other channels parallel to the electrical axis (X) which are larger than the previous ones. In order to compare the influence of each kind of sweeping on the quality of quartz resonator, we have performed Z- and X-sweeping on natural and cultured quartz bars used to manufacture 10 MHz SC-cut resonators. As usually, the process of qualification has been achieved by comparisons between spectrometric measurements (infrared, laser absorption, ICP) before and after treatments.