View source for Specific Process Knowledge/Thin film deposition/ALD Picosun R200/ZnO deposition using ALD/Obsolete

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The ALD window for deposition of zinc oxide (ZnO) ranges from 100 <sup>o</sup>C to 250 <sup>o</sup>C. Several investigation techniques has been implemented for ZnO characterization. Additionally, more information on ZnO can be found on a page about [[Specific_Process_Knowledge/Thin_film_deposition/ALD_Picosun_R200/AZO_deposition_using_ALD|Al-doped ZnO (AZO)]]

All results shown on this page have been obtained using the "ZnOT" recipe on new Si(100) wafers with native oxide: 

=ZnO ALD deposition=
<b>Evgeniy Shkondin, DTU Danchip, 2014-2016.</b>
==ZnO standard recipe==

<b>Recipe: ZnOT</b>

<b>Maximum deposition thickness: 100 nm</b>

<b>Temperature: 100 <sup>o</sup>C - 250 <sup>o</sup>C</b>

{| border="2" cellspacing="2" cellpadding="5"  align="none"
|- 
|
!DEZ<sup>*</sup>
!DEZ
!H<sub>2</sub>O
!H<sub>2</sub>O
|-
!Nitrogen flow
|150 sccm
|150 sccm
|200 sccm
|200 sccm
|-
!Pulse time
|0.1 s
|0.1 s
|0.1 s
|0.1 s
|- 
!Purge time	
|0.5 s
|20.0 s
|0.5 s
|20.0 s
|-
|}
<strong>DEZ</strong> is diethylzinc Zn(CH<sub>2</sub>CH<sub>3</sub>)<sub>2</sub> or ZnEt<sub>2</sub>
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==ZnO deposition rates and uniformity==


The deposition rate for ZnO depends on the temperature, see the ALD-window graph below.  The uniformity, thickness, refractive index has been obtained using [[Specific_Process_Knowledge/Characterization/Optical_characterization#Ellipsometer|Ellipsometer VASE]].


<gallery caption="" widths="700px" heights="300px" perrow="2">
image:ALD_growth_rate_ZnO.jpg|Figure 1. a) Linear growth (~0.15 nm/cycles) @ 200 <sup>o</sup>C. b) ALD-window for ZnO deposition.
image:ALD_SE_ZnO.jpg|Figure 2. a) Typical uniformity profile across 100mm Si wafer based on 49 mesurement points. b) Photography of the prepared wafer.
</gallery>

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==ZnO XPS investigation for elemental trace analysis and deposition on high aspect ratio structures==

XPS profile for ZnO has been obtained using [[Specific_Process_Knowledge/Characterization/XPS/K-Alpha|XPS K-Alpha]]. ZnO samples reveals (see Figure 3a) chemically high quality films with no observable contaminations in temperature range 100 - 250 <sup>o</sup>C.

The recipe is good for deposition on very high aspect ratio structures (with aspect ratio more than 1:20) such as deep trenches, pillars, pores etc. <b>ZnOT</b> recipe can also be used for deposition on polymers at low temperatures (80-120 <sup>o</sup>C).

<!--Research results based on this recipe can be found here: [http://scitation.aip.org/content/avs/journal/jvsta/34/3/10.1116/1.4947586 LINK] (J. Vac. Sci. Technol. A 34(3), 2016 031605)-->

<gallery caption="" widths="700px" heights="300px" perrow="2">
image:ALD_SEM_ZnO_trenches_ALD.jpg|Figure 3. a) XPS survey scan b) SEM images of ZnO deposited on a Si trenches at 200 <sup>o</sup>C temperature and 700 cycles. Trenches prepered using [[Specific_Process_Knowledge/Etch/DRIE-Pegasus|DRIE-Pegasus]]. Inset image shows the photography of the sample.
</gallery>

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<b>Evgeniy Shkondin, DTU Danchip, 2014-2016.</b>
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