Black lithium niobate SAW device fabrication and performance evaluation

Chemically reduced lithium niobate wafers exhibit higher DC electrical conductivity and increased near-UV optical absorption. The higher electrical conductivity minimizes pyroelectric effect, and reduces SAW device fabrication and operation difficulties. The nearly non-transparent appearance due to increased optical absorption (thus the term “black”) also positively impacts the photolithography process. This paper describes some recent tests conducted with SAW devices fabricated on black Y cut lithium niobate wafers. These tests confirmed and expanded upon the pioneering work previously reported on chemically reduced 128° rotated-Y cut lithium niobate wafers. Device performance data over temperature and evaluation of the basic SAW device parameters are presented and discussed. Comparisons with regular, untreated Y cut lithium niobate wafers are also made, with some differences highlighted