Ion beam enhanced etching of LiNbO3

Annealing behavior of lithium niobate irradiated with He-ions at 100K

“…X-and z-cut samples of congruent optical grade LiNbO 3 were irradiated with 200 keV He-ions at a temperature at 100 K. Ion fluences of 5 Â 10 15 and 1 Â 10 16 cm À2 were chosen to keep the damage well below the amorphization level [10]. In order to avoid channeling during the irradiation the samples were irradiated 7°off-axis.…”

“…As a consequence the damaged regions are etched in a hydrofluoric solution (HF) without affecting the non irradiated crystal [5][6][7][8]. In combination with selective ion irradiation using standard masking technologies this allows the fabrication of high quality micro-and nano-structures with high aspect ratios and low roughness in LiNbO 3 [9,10]. In order to generate vertical patterns buried damaged layers are produced using appropriate irradiation conditions.…”

Fabrication of free-standing lithium niobate nanowaveguides down to 50 nm in width

“…In our simulation, we took into account the experimental ion irradiation conditions and material parameters of the LiNbO 3 substrate and of the lithographically patterned mask. For the subsequent etching simulation, we used the dependence of the etch rate on the defect concentration that was obtained experimentally [42]. Since waveguides are invariant in propagation direction, we performed our simulations only for two-dimensional crosssections of the waveguides.…”

“…However, the shapes of the resulting patterns are very limited due to their strongly inclined sidewalls [37][38][39][40][41] that originate from the isotropic etching behavior. A more suitable pattern transfer technique is ion-beam enhanced etching (IBEE) [42], which was specifically developed for high aspect ratio nanostructures in LiNbO 3 [43,44]. Basically, IBEE uses ion-beam irradiation to damage the crystal structure of the LiNbO 3 .…”

Ion-beam induced effects at 15K in LiNbO3

“…A very interesting material for optical applications is lithium niobate ðLiNbO 3 Þ because it possesses large electro-optical, piezoelectric and nonlinear optical coefficients. The ion irradiation changes for example the refractive index and the chemical resistance due to the generated defects [1][2][3]. But for a successful application of this method for the fabrication of optical devices, the formation of irradiation induced defects has to be understood.…”