No abstract

Low temperature epitaxial growth of group-IV alloys is a key process step to realize the advanced Si-based devices. In order to keep high growth rate below 600 °C, trisilane (Si3H8) was used for their growth as an alternative Si precursor gas. Then, we compared the use of Si3H8 versus SiH4 for Si1-xGex growth in H2 and N2 as carrier gas by low temperature chemical vapor deposition. By using Si3H8 and controlling GeH4 flow rate, Si1-xGex growth with high growth rate and wide range of Ge concentration has been achieved compared to SiH4-based process. The growth rate and Ge concentration in Si1-xGex with Si3H8 grown at 600 °C ranged from 11 to 74nm/min and from 0 to 40%, respectively. The obtained growth rates with Si3H8 are between 1.5 and 6 times higher than for SiH4 at a given growth condition. Si3H8-based in-situ B-and C-doped Si1-xGex growth with high growth rate was also demonstrated.

Spectroscopic ellipsometry (SE) model was developed to study substrate loss of shallow implanted silicon substrate following photoresist strip. Model is based on different optical properties of silicon oxide (SiO 2 ) and implanted silicon (i-Si) layers and silicon substrate, and is used to characterize relevant layers, i-Si and SiO 2 , before and after plasma treatment. The increase in SiO 2 and decrease in i-Si layer was observed after plasma exposure. Changes in i-Si layer are the result of two phenomena, oxidation and heating induced re-growth of i-Si layer, while changes in SiO 2 thickness represent direct measure of substrate loss due to oxidation. Good agreement between TEM and SE measurements confirms that SE model can distinguish between crystalline (c-Si) substrate and i-Si, regardless if i-Si is only damaged, d-Si (crystalline) or amorphized, a-Si after implantation. We have also found consistency in SIMS dopant profiles and substrate losses extracted from SE measurements for plasma processes studied.