Interfacial perfection for pushing InGaAs and Ge MOS device limits (invited)

The in-situ deposited high κ gate dielectrics, Ga 2 O 3 (Gd 2 O 3 )[GGO], Y 2 O 3 , HfO 2 , and Al 2 O 3 , on freshly molecular beam epitaxy (MBE) grown In 0.53 Ga 0.47 As (InGaAs) have perfected the interfacial electronic (chemical) characteristics, thus achieving low interfacial trap densities (D it ) and high-temperature thermal stability. These enable fabrication of self-aligned inversion- channel InGaAs metal-oxide-semiconductor field-effect- transistors (MOSFETs) using a CMOS compatible process, giving very high drain currents (I d ) of 1.05-1.8 mA/μm and transconductances (G m ) of 0.714-0.98 mS/μm in 1μm gate length (L g ) devices; Synchrotron radiation photoemission spectroscopy (SRPES) reveals no AsO x residue at the in-situ atomic layer deposited (ALD)-Al 2 O 3 /InGaAs interface, while some AsO x remains using the ex-situ method. The in-situ 1μm L g GGO/Ge pMOSFETs have given I d of 0.496 mA/μm, G m of 0.178 mS/ μm, and effective hole mobility of 389 cm 2 /V s. On the formation of Schottky barrier height (SBH) of Ag/GaAs, SRPES core-level data show that Ag adatoms effectively passivate the surface As-As dimers in the initial Ag deposition. A SBH of 0.38 eV is secured at Ag 0.25 A thick prior to the formation of an Ag metal. The final SBH is similar to the measured value at the initial Ag deposition.