View source for Specific Process Knowledge/Thin film deposition/Deposition of Silicon

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PolySilicon can be deposited in several Nanolab tools. It can be sputtered, e-beam evaporated or be deposited in the PolySilicon furnaces. In the chart below you can compare the different deposition methods:


==Deposition of PolySilicon using LPCVD==

DTU Nanolab has two furnaces for deposition of LPCVD (Low Chemical Vapour Deposition) polysilicon: A 6" furnace (installed in 2011) for deposition of standard polySi, amorphous polySi and boron doped polySi on 100 mm or 150 mm wafers and a 4" furnace (installed in 1995) for deposition of standard polySi, amorphous polySi, boron- and phosphorous doped polySi on 100 mm wafers. In LabManager the two furnaces are named "Furnace: LPCVD Poly-Si (4") (B4)" and "Furnace: LPCVD Poly-Si (6") (E2)", respectively. 

*[[Specific_Process_Knowledge/Thin_film_deposition/Deposition_of_polysilicon/Deposition_of_polysilicon_using_LPCVD/Standard_recipes,_QC_limits_and_results_for_the_4%22_polysilicon_furnace|Deposition of polysilicon using the 4" polysilicon furnace]]
*[[Specific_Process_Knowledge/Thin_film_deposition/Deposition_of_polysilicon/Deposition_of_polysilicon_using_LPCVD/Standard_recipes,_QC_limits_and_results_for_the_6%22_polysilicon_furnace|Deposition of polysilicon using the 6" polysilicon furnace]]

==Deposition of Silicon using PECVD==

At Nanolab you can also deposit silicon the using PECVD. The deposition temperature is 300 °C.  

* [[/Si deposition using PECVD|Si deposition using PECVD3]]

==Deposition of Silicon using sputter deposition==

At Nanolab we can sputter silicon the using Wordentec or the Lesker Sputter systems. One of the advantages of sputtering is that you can deposit on almost any material you like. 

* [[Specific Process Knowledge/Thin film deposition/Si sputter in Wordentec|Si sputter deposition in the Wordentec]]
* [[Specific Process Knowledge/Thin film deposition/Deposition of Silicon/Si sputter in Sputter-System Lesker|Si sputter deposition in the  Sputter-System (Lesker)]] - ''includes information on surface roughness and stress''
* [[Specific Process Knowledge/Thin film deposition/Deposition of Silicon/Si sputter in Sputter-System Metal-Oxide(PC1)|Si sputter deposition in the  Sputter-System Metal-Oxide(PC1)]]
* [[Specific Process Knowledge/Thin film deposition/Deposition of Silicon/Si sputter in Sputter-System Metal-Oxide(PC3)|Si sputter deposition in the  Sputter-System Metal-Oxide(PC3)]]

It was previosly possible to sputter Si with our [[Specific Process Knowledge/Etch/IBE⁄IBSD Ionfab 300| IonFab 300]]. You can read about the deposition conditions and results from that [[Specific Process Knowledge/Etch/IBE⁄IBSD Ionfab 300/IBSD of Si|here]].

==Deposition of Silicon using e-beam evaporation==
It is possible to e-beam evaporate silicon at Nanolab using the [[Specific Process Knowledge/Thin film deposition/10-pocket e-beam evaporator|E-beam evaporator (10-pockets)]]. As with sputtering you can deposit on almost any material. In e-beam evaporation the deposition is line-of-sight and will be suitable for lift-off. However for 8" wafers the system is not optimized for lift-off on the full diameter of the wafer.

==Comparison of the methods for deposition of Silicon==

{| border="1" cellspacing="0" cellpadding="3" 
|-style="background:silver; color:black"
! 
! 4" and 6" Furnace PolySi ([[Specific Process Knowledge/Thin film deposition/Furnace LPCVD PolySilicon|Furnace LPCVD PolySi]])
! PECVD ([[Specific Process Knowledge/Thin film deposition/PECVD|PECVD]])
! Sputter ([[Specific Process Knowledge/Thin film deposition/Wordentec|Wordentec]])
! Sputter ([[Specific Process Knowledge/Thin film deposition/Lesker|Lesker]])
! Sputter ([[Specific Process Knowledge/Thin film deposition/Cluster-based multi-chamber high vacuum sputtering deposition system|Sputter-system Metal-Oxide (PC1) and Sputter-system Metal-Nitride (PC3)]])
! E-beam evaporation ([[Specific Process Knowledge/Thin film deposition/10-pocket e-beam evaporator|E-beam evaporator (10-pockets)]])
|- 
|-style="background:WhiteSmoke; color:black"
! General description

| LPCVD (low pressure chemical vapour deposition) of a-Si and poly-Si
| Plasma Enhanced Chemical Vapor Deposition of Si
| Sputter deposition of Si.
| Sputter deposition of Si. 
| Sputter deposition of Si. 
| E-beam evaporation of Si.
|-

|-style="background:LightGrey; color:black"
! Doping facility
|Yes, B (boron) and P (phosphorus)
|Yes, B and P
|None
|None
|None
|None
|-
|-style="background:WhiteSmoke; color:black"
! Pre-clean
|New wafers can go directly into the furnace. Processed wafers have to be RCA cleaned
|&nbsp;
|RF Ar clean available
|RF Ar clean available
|RF Ar clean available
|None
|-
|-style="background:LightGrey; color:black"
! Layer thickness
|~5 nm to 2 µm, if thicker layers are needed please ask the furnace team.
|few nm to ~ 600 nm
|few nm to ~ 300 nm
|few nm to >200 nm 
|few nm to ?
|few nm to 100 nm *
|-

|-style="background:WhiteSmoke; color:black"
! Deposition rate
|
*undoped, boron doped:~100 Å/min
*Phosphorous doped:~20 Å/min
|~6 Å/s can probably be higher
|
On the order of 1 Å/s dependent on process parameters. See more [[Specific Process Knowledge/Thin film deposition/Si sputter in Wordentec|here.]]
| Depends on process parameters, roughly 0.2-2 Å/s. See Process Log.
|Depends on process parameters, at least 0.3 Å/s, see conditions [[Specific_Process_Knowledge/Thin_film_deposition/Cluster-based_multi-chamber_high_vacuum_sputtering_deposition_system#Standard_recipe_performance|here]]
| 1 Å/s
|-
|-style="background:LightGrey; color:black"
! Process temperature
|560 °C (amorphous) and 620 °C (poly)
|300 °C
|room temperature
|room temperature
|room temperature to 600 °C 
|room temperature to 250 °C 
|-

|-style="background:WhiteSmoke; color:black"
! Step coverage
|Good
|Medium
|Medium
|Medium
|Medium - may be possible to improve using HIPIMS
|no step coverage unless using tilt holder, in which case the step coverage can be very good and can be tuned.
|-

|-style="background:LightGrey; color:black"
! Adhesion
|Good for fused silica, silicon oxide, silicon nitride, silicon
|Not tested, but do not deposit on top of silicon
|&nbsp;
|&nbsp;
|&nbsp;
|&nbsp;
|-

|-style="background:WhiteSmoke; color:black"
! Batch size
|
*1-30 wafers (4" furnace)
*1-25 wafes (6" furnace)
|
* Several small samples
* 1-2x 50 mm wafer
* 1x 100 mm wafer
* 1x 150 mm wafer
|
*24x 2" wafers or 
*6x 4" wafers or
*6x 6" wafers

|
* Up to 1x6" wafers
* smaller pieces
|
*Up to 10x6" or 4" wafers
*many smaller pieces
|
*Up to 4 x 6" wafer or
*3x 8" wafers (ask for special holder)
*Many smaller pieces 

|-style="background:LightGrey; color:black"
! Allowed substrates 

|
* Silicon wafers (new or RCA cleaned) 
** with layers of silicon oxide or silicon (oxy)nitride 
**  from the A, B and E stack furnaces 
* Quartz/fused silica wafers (RCA cleaned) 
|
*See the cross contamination sheets
|   
*Almost any that does not degas.
|
* Almost any that does not degas, see cross-contamination sheet
|
*Almost any that does not degas, see cross-contamination sheets
|
*Almost any that does not degas, see cross-contamination sheets

|-
|-style="background:WhiteSmoke; color:black"
! Allowed material 

| *Only those above (under allowed substrates).
|
*See the cross contamination sheets
|    
* Almost any that does not degas.

|    
*Almost any that does not degas, see the cross-contamination sheet
|
*Almost any that does not degas, see the cross-contamination sheets
|
*Almost any that does not degas, see cross-contamination sheet

|-


|-style="background:LightGrey; color:black"
! Comment
|
|Only in PECVD3
| 
|
|
| 
|}

'''*''' If you wish to deposit a thicker layer than 100 nm please talk to responsible staff or write to thinfilm@nanolab.dtu.dk