Defects in surface layers of lapped crystal plates and their influence on Q-factors of crystal units

Investigations on crystal elements of AT-cut at 1 Mc vibrating at the main resonance were performed. Using the value of the etching velocity change for lapped crystal elements, the total value of the quartz layer containing defects in the crystal lattice is defined. Two components of this layer are identified. The disposition of these components on the lapped quartz surface is defined, and the contribution of each of the components to the loss value in vibrating crystal elements is computed.<>