[labnetwork] wet etching InGaAlAs

[McWilliams, Scott]

Thank you all for your replies, I will check to see if the peroxide is the issue.  I did etch the nitride with BOE, so didn’t dry etch it.  After the BOE etch I stripped off the photoresist with solvents.  For these wafers, I need to remove an InP layer and then an InGaAsP layer before etching the InGaAlAs.  Regards, Scott

Sent from my iPhone

On Jan 7, 2020, at 4:38 PM, Fouad Karouta <fouad.karouta at anu.edu.au> wrote:


Hi Scott,

Usually the solution you mentioned should be able to etch the material. You may consider using smaller amount of water.
Do you have any other layers on top of the InGaAlAs layer?

Note H2O2 solutions should be made fresh every time of usage.
I used a same solution to etch GaAs/AlAs at RT. Also we did sometime at 0°C.

CH4/H2 process will etch very slowly Al containing materials.

Hope this helps,
Fouad Karouta

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From: labnetwork-bounces at mtl.mit.edu <labnetwork-bounces at mtl.mit.edu> On Behalf Of McWilliams, Scott
Sent: Wednesday, 8 January 2020 7:32 AM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] wet etching InGaAlAs

Hello All,

I’m processing some wafers and need to wet etch layers of InGaAlAs of various compositions (Alx values of x = 0.48 to 0.27).  I pulled a reference from the A.W. Clawson III-V etch reference guide that H3PO4/H202/H20 1:1:10 should etch this material, but it is not etching.  The referenced paper does not provide the etchant temperature.

I suspect that I need to perform a surface etch of some type before etching the InGaAlAs.  We do have the limitation that our current mask is 600 angstroms of silicon nitride, so we may be prohibited from performing  HF containing surface etches.

Does anyone have experience with this material and a recommended surface clean?  Is there a better etchant to use?  Has anyone attempted to dry etch this material with a CH4/H2 process?

Thank you,  Scott
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