[Spm] Depth of narrow trenches

[Susheng Tan]

Hi Youngwoo,

I am very sure the AFM measurement of trench depth like yours is very
reasonable. We've done lots of such kind work with our students with very
satisfied results. The trench depth we have measured ranged from several
nanometers to micrometer. The system in our lab is DI Multimode SPM. You may
have to calibrate your scanner if you are doubt about its accuracy.

Regards,

Susheng Tan
Department of Chemistry
Oklahoma State University
Stillwater, OK 74078
Phone: (405) 744-4835 (AFM Lab.)
       (405) 744-3013 (EM Lab.)
Fax:   (405) 744-6007
Email: susheng.tan at okstate.edu

-----Original Message-----
From: Youngwoo Yi [mailto:Youngwoo.Yi at colorado.edu] 
Sent: Tuesday, July 11, 2006 1:17 PM
To: spm at spmlist.di.com
Subject: [Spm] Depth of narrow trenches


Hello,

My sample is a topographic patterns of lines. The pitches of the lines
varies from ~100 nm to 1000 nm. I am measuring the depth of trench using
contact mode AFM. The depth is much smaller than the expected one. I expect
~ 30 nm but the measurment is only 3 nm. So I dought if the height I measure
is real of not. As the trench becomes narrower it will be harder for the tip
go into the bottom of the trecnch. But considering tip radius of ~20 nm this
happens for trenches of width much larger than the tip radius. Do you know
waht is the limit of heigh measurement for the contact mode AFM?

Can the contact AFM give the accurate depth of the very narrow trenches when
the width of the trench is sub-micron meter? From what size of trench we see
the significant deviation of height from the real height?



--
Youngwoo Yi
Postdoctoral Research Associate
Physics Department and Liquid Crystal Materials Research Center University
of Colorado Boulder, CO 80309

Tel:303-492-4830 (O)
    E-mail: yiy at colorado.edu


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