Plasma Technology  


Linear self-limited growth in the ALD regime


AFM image
of 6 nm HfO2

 

 


Metal precursor: TEMAH (75°C)
Delivery method: bubbled with argon
Non-metal precursor: O2 plasma
Growth rate: 1.0 Å/cycle
Carbon Impurity: < 2 at% at 200°C

with kind permission of
Dr. Hoffmann-Eifert and A. Hardtdegen
PGI, Forschungszentrum Juelich GmbH

HfO2 remote plasma ALD for ReRAM cells


Hafnium oxide for resistive switching memory

Non-volatile resistive switching random access memory (ReRAM) is discussed for ‘beyond Moore’ Green-IT solutions. A switching cell consists of a metal/oxide/metal stack with < 1000 nm2 size and a few nm of oxide thickness. Therefore, ultra-thin, homogenous, pinhole-free, oxide films of controlled purity are required. One approach is the integration of an oxygen exchange layer and a full stoichiometric HfO2 film obtained from plasma assisted ALD. The quality of remote plasma ALD HfO2 films is shown.

 

Typical bipolar-type current voltage characteristic of a cell from 8 nm thick HfO2 between a Pt and a Ti



FlexAL

 


ALD schematic
valve between remote ICP source
and chamber,
spectroscopic ellipsometry optional

 


TEMAH molecule
tetrakis ethylmethylamino hafnium
TEMAH is heated to 75° C and used in
"bubbling mode".

 

 

Stable ALD window within the range
of 260 – 340 °C



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