2022-09-21 10:27 Status: # Furnace A type of oven with a heating element - control the temperature, pressure and atmosphere.  Can place a tray of [Wafers](Wafers.md) in the furnace, and it can process alot of [Wafers](Wafers.md) in one go - cheap! Try to use furnace if possible. ## Diffusion Wafer protected by developed photoresist. Then an atmosphere of phosphorous gas - enters the surface of the silicon due to [concentration gradients](concentration%20gradients.md) and form an n-well.  ## Oxidation Selectively exposed wafer - oxygen available - forms silicon dioxide insulator layer.  Old technology: - [[LOCOS]] - [[Gate Oxides]] ## Chemical Vapour Deposition Chemicals deposited on top of wafer (typically dielectrics, gate oxide, more)  ## Annealing Heating up to high temp and then cooling. Don't want any chemical reactions, so use atmosphere of inert gas (e.g. N2). Dopant profiles smear, but repair the lattice you started with.   Critical in the fabrication of [transistors](transistor.md). [^1] --- # References [^1]: