SELECTIVE EPITAXIAL GROWTH

• if Si is partially covered partially with oxide → Si will grow only on single-crystalline Si, thus the SiO₂ can be used as mask
• it is possible to appear growth also on the oxide however the growth rate is much lower: SiO₂ < Si₃N₄ < Si

• Problems:
  • Si nodules may appear on SiO₂ and HCl is necessary to etch them (HCl is added in the reactor with the other gases)
  • Growth rate dependence with window size (see picture) can cause problems
  • Faceting - growth rate dependence on crystal planes
• ELO - extended lateral growth
  • problems with defects in the area where Si join together over the oxide