In this study, we evaluated the electrical properties of the bonded silicon-on-insulator (SOI) wafers with lifetime measurements using a
non-contact laser-microwave method
. We prepared one group that consisted of bonded SOI wafers with different active layer thicknesses (I0,30,100μm) and another group consisting of bonded SOI wafers with different buried oxide layer thicknesses(0,0.01,0.1,0.75μm). Primary mode lifetime (τ1) was measured by the
photoconductivity decay (PCP) method
using the laser diode (λ= 774nm) as a carrier-injected light source. Steady-state change in the conductivity was measured by the
photoconductivity modulation (PCM) method
using a He-Ne laser (λ = 633nm) as a carrier-injected light source. τ1 decreases as the active layer thickness decreases. The PCM intensity also decreases with decreasing active layer thickness. Surface and interface recombination rates of the SOI are increased with decreasing layer thickness. The PCM intensity also decreases as the buried layer thickness decreases.