Wednesday, January 27, 2016

IBM Research present InGaAs on insulator FinFET process using Plasma Enhanced ALD HKMG

IBM Research GmbH in Switzerland has developed an n-channel indium gallium arsenide (InGaAs) on insulator fin field-effect transistor (FinFET) process and claims the highest on-current to date for CMOS-compatible InGaAs devices integrated on silicon (Si) [Vladimir Djara et al, IEEE Electron Device Letters, published online 1 January 2016].

According to the paper, the devices were fabricated using a replacement metal gate (RMG) flow, including ultra-thin SiN spacers, scaled high-k/metal gate (HKMG), and highly-doped raised source and drain (RSD) modules for improved electrical performance.

ALD Inside:
  • 12-nm-thick SiN spacers were deposited by plasma-enhanced atomic layer deposition (PEALD)
  • After dummy gate removal, a HKMG, featuring a scaled Al2O3/HfO2 dielectric stack with a capacitance equivalent thickness (CET) of ∼1.5 nm, was deposited using a highly conformal and uniform PEALD process. the process has previously been published here.  The tool used is a FlexAL ALD from Oxford Instruments and the PEALD processes are TMA and O2 plasma for Al2O3 and TEMAH and O2 plasma for HfO2.
The FlexAL® systems provide a new range of flexibility and capability in the engineering of nanoscale structures and devices by offering remote plasma atomic layer deposition (ALD) processes and thermal ALD within a single ALD system.

Pretty cool if you ask me to see that PEALD is used for gate dielectric, which is usually not the case on silicon channels where thermal HfCl4/H2O process is dominating and also that TEMAHf can perform this good as a gate dielectric. Please read the full report in Semiconductor Today here.