Atomic-layer-deposited LaAlO3/SrTiO3 all oxide field-effect transistors

We have demonstrated well-behaved accumulation-mode all oxide NMOSFETs with amorphous atomic-layer-deposited (ALD) LaAlO
₃
gate dielectric stacks on crystalline SrTiO
₃
substrates. A maximum drain current exceeding 10 mA/mm has been obtained on a 3.75μm-gate-length device, proving a very conductive channel can be formed at the oxide-oxide interface. Four different gate dielectric stacks, which are Lafirst cycle LaAlO
₃
, Al-first cycle LaAlO
₃
, LaAlO
₃
with 1.5 nm La
₂
O
₃
interfacial layer, and LaAlO
₃
with 1.8 nm Al
₂
O
₃
interfacial layer, have been deposited on SrTiO
₃
substrates to systematically study their effects on the conductivity at the different oxide-oxide interfaces. The experimental results show that a La-initiated interfacial layer is preferable to form a more conducting channel at the LaAlO
₃
/SrTiO
₃
interface. Low temperature characteristics have also been utilized to provide an in-depth understanding of the channel formation at the oxide-oxide interface. The availability of the MBE technology to epitaxially grow SrTiO
₃
on Si substrate provides the pathway to integrate ALD LaAlO
₃
/SrTiO
₃
devices on Si platform.