Published online by Cambridge University Press: 22 February 2016
In this paper, we will report on the formation of HfSixOylayer on an HF-last Si(100) substrate by atomic layer deposition fromtetrakis(dimethylamido)hafnium (TDMAH) and atomic oxygen generated by amicrowave remote plasma. Transmission electron microscopy observations ofHfSixOy /Si structures deposited at 100 and300℃ revealed that 3∼5-nm-thick amorphousHfSixOy layers were unintentionally formed precededthe growth of crystalline Hf-rich HfSixOy layers. Tounderstand the mechanism of this unintentional growth ofHfSixOy, the depth profiles of Hf, O and Si elements weremeasured by X-ray photoelectron spectroscopy. It was found that Hf atoms deeplydiffused into the Si substrate. From these results, suppression of Hf indiffusion to the Si substrate must be important to reduce the capacitanceequivalent thickness of the metal-oxide-semiconductor capacitors. The roles ofTDMAH and plasma-generated oxygen radical on the enhanced diffusion of Hf willbe discussed in detail.