Ablation and compaction of amorphous SiO2 irradiated with ArF excimer laser

Photo-induced phenomena in GeO2 glass

“…Such an opposite behavior also appears in GeS2; i.e., as-evaporated GeS2 films undergo photo-bleaching, while bulk GeS2 provides photo-darkening [9]. Notable differences have been pointed out also for SiO2 [3,11]. We will see in the present study that GeO2 glass exhibits unique photo-induced changes, which are different from those in the sputtered films and also in SiO2 and GeS2 bulk glasses.…”

“…Nevertheless, in consistent with different bonding angles of Si(Ge)-O(S)-Si(Ge), the units in Si(Ge)O2 are connected in a corner-shared way, while GeS2 contains edge-shared connections [49], which can be regarded as 2-membered rings. On the other hand, Si(Ge)O2 are believed to contain small rings such as 3-and 4-membered [11,40], and as noted above, GeO2 may contain a little amount of GeO6/2 units [46].…”

“…It is suggested that, in SiO2, the volume compaction occurs with formation of small rings [11]. In contrast, in GeO2, the volume expansion can be related with the reductions of GeO6/2 units and small rings.…”

Laser-induced defects in fused silica by UV laser irradiation

“…While the exact process is uncertain, the end results are localized physical, chemical, and structural changes of the material exposed to the laser beam. These alterations can be involved with densification, refractive index changes, and/ or defects formation [7][8][9].…”

Fluorinated silica glass ablated with ArF excimer laser at low fluence

“…Thus, laser ablation is of interest as a dry method for this purpose [3]. In our previous reports, the threshold of ablation was observed at a fluence of 1 J/cm 2 under ArF excimer laser irradiation on thermally-grown a-SiO 2 on silicon [4]. It is clearly important to reduce the threshold fluence to allow laser ablation to create holes in dielectric films.…”