ELEG 450/650 - Key Procedures for Field Oxidation
Cleaning (001) p-type 1-10 W -cm Resistivity Si SubstratesUse teflon tweezers
1-Organics Etch (Pyrex beaker)
-H2SO4:H2O2 (4:1): Etch 10 minutes for removal of residual organic materials. Highly reactive and exothermic etch.
-Rinse 2X in De-ionized Water (DI)
2-Metals Etch (Pyrex beaker)
-H2O:HCl:H2O2 (1:1:1): Let reaction begin, then etch 10 minutes for removal of metallic impurities. This etch also is reactive and exothermic.
-Rinse 2X in DI water
3-Final HF strip (Teflon beaker)
-Dip Si wafers in H2O:HF (20:1) for approximately 20-30s to remove the surface oxide formed during the previous two etches. The sample should be hydrophobic (i.e. repels water)
-Rinse in DI water
-Dry in pure N2
The samples are clean and are ready to be loaded
Oxidation
I will have furnace hot already (T~1100 (C). I have previously taken the temperature profile and the quartz boat has previously been cleaned in an RCA type clean (same as above etch procedure). Before class I will have steam cleaned the furnace with very diluted HCl acid, which acts to getter some harmful impurities.
-Slowly load sample into hot zone. Use correct glassware
-Dry oxidation for one hour. O2 flow is set at 4 (no bubbler).
-wet oxidation for one hour. O2 flow is set at 4. Oxygen is bubbling moderately through a 20:1 solution of H2O:HCl which is held at 90 (C.
-Dry oxidation for one hour. O2 flow is set at 4 (no bubbler)
-unload slowly
I recommend reading (at least skimming) the section on thermal oxidation of Si in Ghandi pp.451-481.
ELEG 450/650 - Key Procedures for Positive Photolithography and forming the Oxide Diffusion barrier for Source and Drain
Photolithography
Etch Openings in Field Oxide for Diffusion of Source/Drain Regions
ELEG 450/650 - Key Steps in Diffusing Phosphorus to form Source and Drain
Cleaning wafers for diffusion
Use teflon tweezers
1-Organics Etch (Pyrex beaker)
-H2SO4:H2O2 (4:1): Etch 10 minutes for removal of residual organic materials. Highly reactive and exothermic etch.
-Rinse 2X in De-ionized Water (DI)
2-Metals Etch (Pyrex beaker)
-H2O:HCl:H2O2 (1:1:1): Let reaction begin, then etch 10 minutes for removal of metallic impurities. This etch also is reactive and exothermic.
-Rinse 2X in DI water
3-Final HF strip (Teflon beaker)
-Dip Si wafers in H2O:HF (20:1) for approximately 20-30s to remove the surface oxide formed during the previous two etches. The sample should be hydrophobic (i.e. repels water)
-Rinse in DI water
-Dry in pure N2
The samples are clean and are ready to be loaded into diffusion furnace.
Phosphorus Diffusion
I will have furnace hot already (T~860 (C). I have previously taken the temperature profile. Before class I will have steam cleaned the furnace with very diluted HCl acid, which acts to getter some harmful impurities.
Electrical Engineering | comments
to: kolodzey@ee.udel.edu
ŠUniversity of Delaware