Metal-oxide-semiconductor (MOS) and MOS field-effect-transistors (MOSFETs) of high k dielectrics on high carrier mobility channels of InGaAs and Ge have been feverishly studied, as they are now strongly considered for technologies beyond Si complementary MOS (CMOS) integrated circuits (ICs). The post Si CMOS research is now facing unprecedented challenges in materials and physics, as key material/electrical/processing issues have to be met/solved in order to realize the new advanced devices; these include equivalent oxide thickness (EOT) < 1 nm, interfacial density of state (Dit) ≤ 1011 eV-1cm-2, high-temperature thermal stability for self-aligned process, low parasitic, and integration with Si. Using in-situ ultra high vacuum (UHV) and in-situ/ex-situ atomic layer deposited (ALD) high k’s of Ga2O3(Gd2O3), Al2O3, and HfO2 on InGaAs and Ge, this research group has made advances in achieving an EOT of 0.5 nm, Dit of low 1011 eV-1cm-2(with a flat distribution versus energy within the semiconductor bandgap), and high-temperature stability of the MOS structures (rapid thermal annealing to 800-900°C and 500-600°C for the high k’s/InGaAs and /Ge, respectively). Atomic manipulation to perfecting the high k’s/InGaAs and /Ge interfaces is the key for the above achievements. Probing of the interfaces and gaining insightful understanding of the electronic properties was made possible using our uniquely designed experiments of in-situ synchrotron radiation photoemission. High-performance self-aligned inversion-channel high k’s/InGaAs MOSFETs in achieving record-high drain currents and transconductances, and record-low sub-threshold swings, and high k’s/Ge MOSFETs without employing interfacial passivation layers will also be discussed.