Team:Cambridge/Protocols/Substrate Preparation for Flow Coating and Spin Coating

From 2011.igem.org

(Difference between revisions)
(Created page with "{{Template:Team:Cambridge/CAM_2011_TEMPLATE_HEAD}} __NOTOC__ ==Protocol Name== Methods used to prepare and clean the substrates we used for flow coating and spin coating. ===The...")
 
(23 intermediate revisions not shown)
Line 1: Line 1:
-
{{Template:Team:Cambridge/CAM_2011_TEMPLATE_HEAD}}
+
{{Template:Team:Cambridge/CAM_2011_PROTOCOL_HEAD}}
-
__NOTOC__
+
==Substrate preparation==
-
 
+
Methods used to prepare the silicon substrates for flow coating and spin coating.
-
==Protocol Name==
+
-
Methods used to prepare and clean the substrates we used for flow coating and spin coating.
+
===Theory===
===Theory===
-
Cut the silicon pieces to size and wash them to remove surface debris, thus improving the properties of the films.
 
-
Various methods were employed, the best films seemed to come from high pressure washing with liquid CO2 (performed by Dr Matthew Hawkeye)
+
The silicon pieces were cut to size and treated with various methods to remove surface debris.
-
Substrates can be either washed in acetone whilst being sonicated and baked in an O2 plasma oven or Washed with high pressure, liquid CO2. The acetone dissolved contaminants whilst sonication vibrates the crystals to make loosely attached debris become free, whilst the O2 plasma oven introduces an excess of reactive oxygen species to burn off any organic contaminants.
+
'''''<FONT COLOR="0000FF">Note: A clean interface is essential for providing good contact for thin films.</FONT>'''''
 +
 
 +
Various methods were employed during our thin film making.
 +
# Acetone bath and sonication followed by either by O<sub>2</sub> plasma oven or high pressure jet wash with liquid CO<sub>2</sub> (CO<sub>2</sub> is used for its sublimation property at room temperature)
 +
# 'Piranha Solution', a potent bath of concentrated sulphuric acid and hydrogen peroxide
 +
 
 +
The methods are all either based upon cleaning up organic contaminants and debris via some chemical reaction like the introduction of oxygen radicals or by physical removal like the pressure wash.  
-
CO2 pressure washing physically displaces debris and leaving a smooth surface for spin and flow coating as it rapidly evaporates.
 
===Practice===
===Practice===
-
Silicon substrates are cleaved using a diamond scribe to introduce a fine nick in the surface of the single silicon crystal. Then upward pressure at the nick and downward pressure at the edges of the crystal an be used to gently and precisely fracture the silicon in two.
 
-
Acetone bath and sonication is achieved by placing the substrates in a rack and placing in a beaker filled with enough acetone to cover them. This is covered with foil and placed in a sonicator for 10 minutes. Following this the O2 plasma oven can be used to burn off contaminants, we used 10 minutes in this oven to make sure our samples were clean.
+
====<FONT COLOR="700000"> Cutting Silicon to Size </FONT>====
 +
# Introduce a fine nick in surface of single-crystal silicon wafer
 +
# Gently bend upwards to precisely fracture the silicon in two
 +
# Repeat until desired dimensions reached
-
CO2 pressure washing was not performed by us, and is as simple as pointing the pressure washer and pulling the trigger. This is performed in a fumehood and uses a strong vacuum to stabilize the sample during washing.
+
'''<FONT COLOR="0000FF">Notes: These silicon wafers are single crystal and have one orientation(100). Introduction of a 'directed' crack 'seeds' a defect into the surface by introducing a stress concentration. Subsequent Application of bending elicits fracture propagation along the defect direction</FONT>.  
 +
====<FONT COLOR="700000"> Interface Cleaning </FONT>====
 +
[[File:Cam_O2_Plasma_Oven.JPG |200px|thumb| left | Silicon Substrates in the O2 Plasma Oven]]
 +
=====Acetone Bath and Sonication=====
 +
# Place the substrates in a rack and submerge in beaker of acetone
 +
# Cover with foil to prevent outside debris and sonicate at standard settings for 10mins
 +
 +
=====O<sub>2</sub> Plasma=====
 +
# Following solvent cleaning place samples in plasma oven for 10 minutes. (time can be adjusted depending on purity levels)
 +
 +
=====Piranha Solution=====
 +
# Fill beaker with 50% HPLC grade sulphuric acid and 50% hydrogen peroxide HPLC grade
 +
# Place beaker on hot plate at 100<sup>o</sup>c
 +
# Place all the prepared silicon wafers within the beaker (It does not matter if the silicon wafers overlap)
 +
# Leave for approximately 10 mins or when bubbling subsides.
 +
# When ready to spin take out desired silicon wafer for spinning, rinse with distilled water and blow dry with N<sub>2</sub> gas.
 +
 +
As explained to me by the lab researchers in the Thin Films Group absolutely nothing survives the piranha bath!
===Safety===
===Safety===
-
Acetone was kept in squirt bottles in the fume hood, as was the beaker containing the substrates during sonication. Foil was used to keep debris out and acetone in the beaker. The O2 plasma oven was a self contained unit, operated and loaded by Dr Matthew Hawkeye, as was the CO2 pressure washer.
+
* Kept acetone in squirt bottles and piranha solution in the fume hood.
 +
* Kept beaker containing substrates during sonication also in fume hood with foil to keep out debris
 +
* The O2 plasma oven and CO<sub>2</sub> pressure washer were self contained units, operated and loaded by Dr Matthew Hawkeye.
 +
* Always wear nitrile gloves and lab coat when handling such concentrated solutions of sulphuric acid and hydrogen peroxide.
 +
 
 +
'''Note of advice: Carry out all work in fume hoods even if it is safe not to do so. You are working with a lot of solvents and vapours which are potentially hazardous to health. Better safe than sorry!'''
-
{{Template:Team:Cambridge/CAM_2011_TEMPLATE_FOOT}}
+
{{Template:Team:Cambridge/CAM_2011_PROTOCOL_FOOT}}

Latest revision as of 20:36, 21 September 2011

Loading...
OVERVIEW
home
Back to Protocols

Contents

Substrate preparation

Methods used to prepare the silicon substrates for flow coating and spin coating.

Theory

The silicon pieces were cut to size and treated with various methods to remove surface debris.

Note: A clean interface is essential for providing good contact for thin films.

Various methods were employed during our thin film making.

  1. Acetone bath and sonication followed by either by O2 plasma oven or high pressure jet wash with liquid CO2 (CO2 is used for its sublimation property at room temperature)
  2. 'Piranha Solution', a potent bath of concentrated sulphuric acid and hydrogen peroxide

The methods are all either based upon cleaning up organic contaminants and debris via some chemical reaction like the introduction of oxygen radicals or by physical removal like the pressure wash.

Practice

Cutting Silicon to Size

  1. Introduce a fine nick in surface of single-crystal silicon wafer
  2. Gently bend upwards to precisely fracture the silicon in two
  3. Repeat until desired dimensions reached

Notes: These silicon wafers are single crystal and have one orientation(100). Introduction of a 'directed' crack 'seeds' a defect into the surface by introducing a stress concentration. Subsequent Application of bending elicits fracture propagation along the defect direction.

Interface Cleaning

Silicon Substrates in the O2 Plasma Oven
Acetone Bath and Sonication
  1. Place the substrates in a rack and submerge in beaker of acetone
  2. Cover with foil to prevent outside debris and sonicate at standard settings for 10mins
O2 Plasma
  1. Following solvent cleaning place samples in plasma oven for 10 minutes. (time can be adjusted depending on purity levels)
Piranha Solution
  1. Fill beaker with 50% HPLC grade sulphuric acid and 50% hydrogen peroxide HPLC grade
  2. Place beaker on hot plate at 100oc
  3. Place all the prepared silicon wafers within the beaker (It does not matter if the silicon wafers overlap)
  4. Leave for approximately 10 mins or when bubbling subsides.
  5. When ready to spin take out desired silicon wafer for spinning, rinse with distilled water and blow dry with N2 gas.

As explained to me by the lab researchers in the Thin Films Group absolutely nothing survives the piranha bath!

Safety

  • Kept acetone in squirt bottles and piranha solution in the fume hood.
  • Kept beaker containing substrates during sonication also in fume hood with foil to keep out debris
  • The O2 plasma oven and CO2 pressure washer were self contained units, operated and loaded by Dr Matthew Hawkeye.
  • Always wear nitrile gloves and lab coat when handling such concentrated solutions of sulphuric acid and hydrogen peroxide.

Note of advice: Carry out all work in fume hoods even if it is safe not to do so. You are working with a lot of solvents and vapours which are potentially hazardous to health. Better safe than sorry!

Back to Protocols

Retrieved from "http://2011.igem.org/Team:Cambridge/Protocols/Substrate_Preparation_for_Flow_Coating_and_Spin_Coating"