Atomic layer deposition of SiO₂ for the performance enhancement of fin field effect transistors

Atomic layer deposition (ALD) of SiO₂ by using a tetraethoxysilane (TEOS) or a bis(ethylmethylamino)silane (BEMAS) have been studied for the side-wall spacer formation of the fin field effect transistor (FinFET). The ALD-SiO₂ can be deposited conformally at 50 °C for the TEOS and at 250 °C for the BEMAS precursor. As a result, FinFETs with a 25-nm-long extension of the source/drain using the ALD grown SiO₂ sidewall spacer have been successfully fabricated. The performance of the FinFET has been successfully improved by reduction of the parasitic resistance.