Structure of high-reflectance La/B-based multilayer mirrors with partial La nitridation

We investigate a hybrid thin film deposition procedure that significantly enhances reflectivity of La/B based nanoscale multilayer structures to be used as Extreme UV mirrors at 6.7 nm wavelength and beyond. We have analyzed the La-nitridation process in detail, and proposed a growth mechanism and deposition procedure for full, stoichiometric passivation of La, avoiding the formation of optically unfavorable BN formation at the LaN-on-B interface. A partial nitridation was applied and studied as a function of the nitridation delay.