Properties and growth peculiarities of Si0.30Ge0.70 stressor integrated in 14 nm fin-based p-type metal-oxide-semiconductor field-effect transistors

Abstract

Integration of Si0.30Ge0.70 in the Source/Drain (S/D) areas of metal oxide semiconductor transistors built according to 14nm technological node rules has been shown. SiGe properties and growth peculiarities are presented and elaborated. In order to preserve the fin structures during a pre-epitaxy surface preparation, the H2 bake pressure had to be increased to 19,998Pa at 800°C. Influence of this bake on the Si recess in the S/D areas is presented. Excellent quality of both the raised and the embedded Si0.30Ge0.70 was demonstrated by transmission electron microscopy inspections. Energy-dispersive X-ray spectroscopy measurement showed two stages of SiGe growth for the embedded case: first with a lower Ge content at the beginning of the deposition until the (111) facets are formed, and second with a higher Ge content which is governed by the growth on (111) planes. Nano-beam diffraction analysis showed that SiGe grown in the S/D areas of p-type metal-oxide-semiconductor field-effect transistor is fully elastically relaxed in the direction across the fin and partially strained along the fin. Finally, a strain accumulation effect in the chain of transistors has been observed.