[labnetwork] Dry etching Zinc Sulfide and/or Zinc Selenide bulk samples

[Fouad Karouta]

Dear Jerry,

Though I have never etched these materials the best way to check the adequate chemistry for dry etching is to look in the Handbook, Section "Physical Constants of compounds" at the melting/boiling points of the possible etching products. You cannot etch a compound if etching products are not volatile.

Most common chemistries used in dry etching are: chlorinated, fluorinated or a mixture of H2/CH4.
S and Se products with fluorine are very volatile however ZnF2 is not volatile
Best etch for zinc is CH4/H2 with organic compound of zinc very volatile.
Am not sure if you mix the two chemistries like SF6 + CH4 and you find a regime where Zn is combined with organic CH3 group and S or Se is combined with F then you may get a decent etch. Maybe using something like CHF3 may work providing CH group reacts with Zn and F with S/Se.

Of course a chlorinated chemistry would do the job but as boiling point of ZnCl2 is relatively high you need to ehat the table to 180-200°C and work at low pressure to increase the volatility while S/SE chlorides are quite volatile.

Hope this helps,
Fouad
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From: labnetwork-bounces at mtl.mit.edu <labnetwork-bounces at mtl.mit.edu> On Behalf Of Shepard, Jeremiah J
Sent: Thursday, 13 February 2020 7:42 AM
To: labnetwork at mtl.mit.edu
Cc: Raghunathan, Nithin <nithin at purdue.edu>; Dilley, Neil R <ndilley at purdue.edu>
Subject: [labnetwork] Dry etching Zinc Sulfide and/or Zinc Selenide bulk samples

Does anyone have experience etching Zinc Sulfide and Zinc Selenide?

It appears chemistry would involve BCL3.

My primary concern is chamber contamination, any experience or thoughts?  Thank you in advance!

Thank you,
Jerry Shepard
Research Engineer
Purdue University
Birck Nanotechnology Center

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