ALD Recipe

Updated on 9/26/2014

 

Contents

1 Basic concept of ALD

2 Process Sequence Table

3 Configuration of precursors

4 Recipes

6 Advanced Page

7 Note

 

1. Basic concept of ALD

Atomic Layer Deposition (ALD) is a technique that allows growth of thin films, atomic layer by layer, using the reaction between precursor and hydroxylated surface. For example, Al2O3 layer is grown from water and trimethylaluminum (TMA), as shown below.

  1. Put in a sample which is hydroxylated from exposure to air, oxygen or ozone (figure A).
  2. Pulse the TMA precursor; TMA will react with the OH groups on the surface. TMA does not react with itself and the monolayer formed passivates the surface (figures B and C).
  3. Remove unreacted TMA molecules by evacuation and/or purging with nitrogen (figure D).
  4. Pulse water (H2O) into the reactor. This will remove the CH3 groups, create Al-O-Al bridges, and passivate surface with Al-OH. CH4 (methane) is formed as a gaseous byproduct (figures E and F).
  5. Remove unreacted H2O and CH4 molecules by evacuation and/or purging with nitrogen (figure G).


See the following review article: Overview_of_ALD

2. Process Sequence Table


2.1 Clicking on the following menu items

2.2 Adding/Changing an instruction (command)

2.3 Example of recipe

The following Process Sequence Table shows an example of recipe:

Detail:

3. Configuration of precursors

Heater 11: Valve 0, H2O, No heater

Heater 12: Valve 1, Trimethylaluminum (TMA) for Al2O3 deposition, No heater

Heater 13: Valve 2, 3-aminopropyltriethoxysilane (APTES) for SiO2 deposition, 105 °C

Heater 14: Valve 3, Tetrakis(dimethylamido)titanium (TDMAT) for TiO2 deposition, 75 °C

Heater 15: Valve 4, Ozone, No heater

Heater 16: Valve 5, Tetrakis(dimethylamino)hafnium (HFDMA), 75 °C


4. Recipes

4.1 Al2O3 deposition

4.1.1 Al2O3 grown with Trimethylaluminum (TMA) and H2O

Growth rates: 0.91 Å/cycle@150°C, 1.0 Å/cycle@200°C, 0.94 Å/cycle@250°C, 1.0 Å/cycle@300°C

Recipe:

Precursors: Al(CH3)3 Trimethylaluminum (TMA), H2O

300°C growth:

250°C growth:

200 °C growth

150°C growth

80°C growth

4.1.2 Al2O3 grown with Trimethylaluminum (TMA) and O3

Growth rates: 0.6 Å/cycle@100°C, 0.9 Å/cycle@250°C

Recipe:

precursors: TMA, O3

250°C growth:

100°C growth:

4.2 SiO2 deposition

4.2.1 SiO2 grown with 3-aminopropyltriethoxysilane (APTES), O3 and H2O

Growth rates: 0.72 Å/cycle@150°C

Recipe:

Precursors: H2N(CH2)3Si(OC2H5)3 3-aminopropyltriethoxysilane (APTES) heated to 105°C

CAS Registry Number#: 919-30-2

water (unheated)

ozone (unheated)

150°C growth:

4.2.2 SiO2 growth with Tris(dimethylamino)silane (TDMASi or TDMAS) and O3

Old Recipe

Precursors: [(CH3)2N]3SiH, Tris(dimethylamino)silane (TDMASi)

CAS#: 15112-89-7

Ozone, O3 (Unheated)


Tris(dimethylamino)silane installed onto port 2, unheated

Ozone installed onto port 4

80-120°C growth:

150-200°C growth:

250°C growth:

300~350°C growth:

New Recipe (9/8/2014)

Reference: SiO2_from_TDMAS_and_ozone_ALD2011

4.3 TiO2 deposition

4.3.1 TiO2 grown with Tetrakis(dimethylamido)titanium (TDMAT) and H2O

CAS#: 3275-24-9

Recipe:

Precursors: Ti(NMe2)4 Tetrakis(dimethylamido)titanium (TDMAT) heated to 75°C and H2O (unheated)

250°C growth:

200°C growth:

150°C growth:

‎

4.3.2 TiO2 grown with Titanium isopropoxide (Ti(O-i-Pr)4) and H2O

Growth rates: 0.123 Å/cycle@120°C, 0.36 Å/cycle@200°C, 0.35 Å/cycle@250°C

Recipe:

Precursors: Ti{OCH(CH3)2}4 Titanium isopropoxide heated to 80°C and H2O (unheated)

250°C growth:

200°C growth:

120°C growth:

4.4 HfO2 deposition

4.4.1 HfO2 grown with Tetrakis(dimethylamino)hafnium (HFDMA) and H2O

Precursors: Hf[N(CH3)2]4, Tetrakis(dimethylamino)hafnium (HFDMA, Hf(NMe2)4) heated to 75°C and H2O (unheated)

250°C growth:

200°C growth:

150°C growth:

100°C growth:

6. Note

  1. Valve number in the above recipes might be changed. Make sure of the valve number of the precursor gas before use.
  2. Ozone dose (pulse time) and O2 flow rate etc. are strongly dependent on the actual setup of your ozone generator. Refer to your ozone generator instructions for recommended settings, and make adjustments if necessary. Limit peak pressure to below 600 Torr during the ozone exposure step to prevent from over pressure or venting to atmosphere.
  3. When an ozone process is aborted or interrupted after the ozone generator is turned on but before the “line ac out 1 0“ command is executed, the ozone generator will be left on indefinitely until turned off manually. If it will not be used soon, run the short recipe below to turn the ozone generator off: line ac out 1 0
  4. N2 flow is turned off during expo steps to allow precursors to have the same exposure over the entire reactor, especially for TDMASi because of its low reactivity.
  5. This recipe works for flat surfaces. For deep vias and trenches, it may not provide adequate precursor dose deep within the pores - increasing exposure time or precursor dose accordingly.