Specific Process Knowledge/Thin film deposition/ALD2 (PEALD): Difference between revisions
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=ALD 2 (PEALD)= | =ALD 2 (PEALD)= | ||
[[Category: Equipment|Thin film]] | [[index.php?title=Category:Equipment|Thin film]] | ||
[[Category: Thin Film Deposition|ALD]] | [[index.php?title=Category:Thin Film Deposition|ALD]] | ||
== Thermal ALD and PEALD == | == Thermal ALD and PEALD == | ||
[[image:ALD2.jpg| | [[image:ALD2.jpg|450x450px|right|thumb|ALD 2 (PEALD). Positioned in cleanroom F-2.]] | ||
The ALD 2 (PEALD) is used to deposit very thin and uniform layers of different materials, by use of thermal ALD (Atomic Layer Deposition) or PEALD (Plasma Enhanced ALD). | The ALD 2 (PEALD) is used to deposit very thin and uniform layers of different materials, by use of thermal ALD (Atomic Layer Deposition) or PEALD (Plasma Enhanced ALD). Layers can be up to 100 nm thick, see the table below. | ||
The ALD deposition takes place in an ALD reactor chamber. In order to ensure that the temperature inside this reactor is the same everywhere, it has a dual chamber structure. The inner chamber is the reactor chamber, and the outer chamber is isolating the reactor chamber from room air. Both the inner and the outer chamber are under vacuum. The space between the two chambers is called an intermediate space (IMS), and the IMS is constantly purged with nitrogen. | The ALD deposition takes place in an ALD reactor chamber. In order to ensure that the temperature inside this reactor is the same everywhere, it has a dual chamber structure. The inner chamber is the reactor chamber, and the outer chamber is isolating the reactor chamber from room air. Both the inner and the outer chamber are under vacuum. The space between the two chambers is called an intermediate space (IMS), and the IMS is constantly purged with nitrogen. | ||
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The liquid precursor sources TMA, TiCl<sub>4</sub> and H<sub>2</sub>O are stored in bottles located in a side cabinet on the left side of the machine. When the TMA and TiCl<sub>4</sub> precursors are not in use, a manual valve on each bottle has to be closed. The powder precursors SAM24 and TEMAHf are stored in bottles located in a big cabinet below the ALD chamber. These precursors are heated by heating jackets, and users should not open and close the manual valves. O<sub>3</sub> is generated by use of an ozone generator that is located in the E-rack at the right side of the machine. | The liquid precursor sources TMA, TiCl<sub>4</sub> and H<sub>2</sub>O are stored in bottles located in a side cabinet on the left side of the machine. When the TMA and TiCl<sub>4</sub> precursors are not in use, a manual valve on each bottle has to be closed. The powder precursors SAM24 and TEMAHf are stored in bottles located in a big cabinet below the ALD chamber. These precursors are heated by heating jackets, and users should not open and close the manual valves. O<sub>3</sub> is generated by use of an ozone generator that is located in the E-rack at the right side of the machine. | ||
A remote plasma generator is connected to the upper part of the reactor chamber. Different precursor gases are connected to this plasma generator through the same gas inlet. | A remote plasma generator is connected to the upper part of the reactor chamber. Different precursor gases are connected to this plasma generator through the same gas inlet. At the moment the available plasma precursor gases are N<sub>2</sub>, O<sub>2</sub>, NH<sub>3</sub> and H<sub>2</sub>. The plasma gas inlet is constantly purged with argon. The plasma gases can also be used as precursors for thermal ALD if the power to the plasma generator is not turned on. When H<sub>2</sub> is being used, the pump line constantly has to be purged with 1.9 SLM nitrogen, and this has to be enabled manually. | ||
The plasma generator is separated from the reactor chamber by a plasma cone (or chamber lid). The argon flow through the plasma gas inlet ensures that the plasma cone remains clean. | The plasma generator is separated from the reactor chamber by a plasma cone (or chamber lid). The argon flow through the plasma gas inlet ensures that the plasma cone remains clean. | ||
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The precursor pulse time is controlled by special ALD valves that allow very short precursor pulses to be introduced into the ALD reactor chamber and at the same time allow a constant nitrogen or argon flow. Thus, nitrogen and argon are always flowing through the ALD valves into the chamber, independent on whether a precursor pulse is introduced or not. | The precursor pulse time is controlled by special ALD valves that allow very short precursor pulses to be introduced into the ALD reactor chamber and at the same time allow a constant nitrogen or argon flow. Thus, nitrogen and argon are always flowing through the ALD valves into the chamber, independent on whether a precursor pulse is introduced or not. | ||
At the moment it is possible to deposit Al<sub>2</sub>O<sub>3</sub>, TiO<sub>2</sub>, HfO | At the moment it is possible to deposit Al<sub>2</sub>O<sub>3</sub>, TiO<sub>2</sub>, HfO<sub>2</sub>, AlN and TiN in the ALD. In order to deposit good quality nitride layers with low sheet resistance, the amount of oxygen has to be very low. Thus, the ALD reactor chamber has to be passivated for about three days, before nitride depositions can be done, and oxides and nitrides cannot be deposited at same time. | ||
Samples are loaded through a load lock. 6" and 8" wafers can be loaded directly in the load lock, while 4" wafers and smaller samples have to be placed on a 6" carrier plate or a 6" silicon dummy wafer with an etched recess. It is only possible to load one wafer or carrier plate at a time by use of the load lock. | Samples are loaded through a load lock. 6" and 8" wafers can be loaded directly in the load lock, while 4" wafers and smaller samples have to be placed on a 6" carrier plate or a 6" silicon dummy wafer with an etched recess. It is only possible to load one wafer or carrier plate at a time by use of the load lock. | ||
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'''Standard recipes on ALD 2 (PEALD):''' | '''Standard recipes on ALD 2 (PEALD):''' | ||
*[[/Standard recipes on the ALD2 tool|Standard recipes on the ALD 2 (PEALD)]] | *[[/Standard recipes on the ALD2 tool|Standard recipes on the <b>ALD 2 (PEALD)</b>]] | ||
''' | '''Available processes:''' | ||
*[[/Al2O3 deposition using ALD2| Al<sub>2</sub>O<sub>3</sub> deposition using '''ALD 2 (PEALD)''']] | *[[/Al2O3 deposition using ALD2| Al<sub>2</sub>O<sub>3</sub> deposition using '''ALD 2 (PEALD)''']] | ||
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*[[/HfO2 deposition using ALD2| HfO<sub>2</sub> deposition using '''ALD 2 (PEALD)''']] | *[[/HfO2 deposition using ALD2| HfO<sub>2</sub> deposition using '''ALD 2 (PEALD)''']] | ||
*[[/AlN deposition using ALD2| AlN deposition using '''ALD 2 (PEALD)''']] | *[[/AlN deposition using ALD2| AlN deposition using '''ALD 2 (PEALD)''']] | ||
*[[/TiN deposition using ALD2| TiN deposition using '''ALD 2 (PEALD)''']] | *[[/TiN deposition using ALD2| TiN deposition using '''ALD 2 (PEALD)''']] | ||
*[[/Al2O3 deposition using plasma ALD2 at room temperature| Al<sub>2</sub>O<sub>3</sub> deposition using '''ALD 2 (PEALD)''' at room temperature]] | |||
'''Obsolete process:''' | |||
*[[/SiO2 deposition using ALD2| SiO<sub>2</sub> deposition using '''ALD 2 (PEALD)''']] | |||
==Equipment performance and process related parameters== | ==Equipment performance and process related parameters== | ||
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*Al<sub>2</sub>O<sub>3</sub> - Thermal Al<sub>2</sub>O<sub>3</sub> (mainly backup for ALD1) and Al<sub>2</sub>O<sub>3</sub> using plasma | *Al<sub>2</sub>O<sub>3</sub> - Thermal Al<sub>2</sub>O<sub>3</sub> (mainly backup for ALD1) and Al<sub>2</sub>O<sub>3</sub> using plasma | ||
*TiO<sub>2</sub> (amorphous or anatase) - Thermal TiO<sub>2</sub> (mainly backup for ALD1) and TiO<sub>2</sub> using plasma | *TiO<sub>2</sub> (amorphous or anatase) - Thermal TiO<sub>2</sub> (mainly backup for ALD1) and TiO<sub>2</sub> using plasma | ||
*HfO<sub>2</sub> - Thermal HfO<sub>2</sub> (mainly backup for ALD1) | *HfO<sub>2</sub> - Thermal HfO<sub>2</sub> (mainly backup for ALD1) | ||
*AlN - AlN using plasma | *AlN - AlN using plasma | ||
*TiN - Thermal TiN and | *TiN - Thermal TiN and TiN using plamsa | ||
Is is not possible to deposit oxides and nitrides at the same time | *ZnO | ||
*AZO | |||
All precursors might not be available at the same time. | |||
Is is not possible to deposit oxides and nitrides at the same time. | |||
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!style="background:silver; color:black" align="center" valign="center" rowspan="2"|Performance | !style="background:silver; color:black" align="center" valign="center" rowspan="2"|Performance | ||
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|style="background:LightGrey; color:black"|Thickness | |style="background:LightGrey; color:black"|Thickness | ||
|style="background:WhiteSmoke; color:black"| | |style="background:WhiteSmoke; color:black"| | ||
*Al<sub>2</sub>O<sub>3</sub>, TiO<sub>2</sub>, HfO<sub>2</sub>: | *Oxides: Al<sub>2</sub>O<sub>3</sub>, TiO<sub>2</sub>, HfO<sub>2</sub>, ZnO, AZO: 0-100 nm | ||
* | *Nitrides: AlN, TiN: 0-100 nm | ||
<i>As the purpose of ALD 2 is to deposit very thin and uniform layers, the allowed deposition thickness is limited to 100 nm, and it is not allowed to do more depositions on the same sample(s) to deposit thicker layers than 100 nm. Deposition of thicker layers is not allowed, because this will occupy the machine for long time and thus make it available for less users. Long depositions also cause issues and with flakes and particles, which means that the chamber and the pump line will have to be cleaned or changed quite often. Furthermore, the delivery time on precursors is usually quite long. So when you make a sample design, you should avoid steps, where you need to deposit thicker layers than 100 nm with ALD, or you can consider, if the same material can be deposited using other machines in the cleanroom.</i> | |||
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!style="background:silver; color:black" align="center" valign="center" rowspan="3"|Process parameter | !style="background:silver; color:black" align="center" valign="center" rowspan="3"|Process parameter | ||
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*O<sub>2</sub> | *O<sub>2</sub> | ||
*NH<sub>3</sub> | *NH<sub>3</sub> | ||
* | *H<sub>2</sub> | ||
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!style="background:silver; color:black" align="center" valign="center" rowspan="3"|Substrates | !style="background:silver; color:black" align="center" valign="center" rowspan="3"|Substrates | ||