We demonstrate high-performance self-aligned In0.53Ga0.47As-channel MOSFETs with effective channel length LEFF down to 20 nm, peak transconductance GMSAT over 2200 μS/μm at LEFF = 30 nm and supply voltage VDD = 0.5 V, thin inversion oxide thickness TINV = 1.8 nm, and low series resistance REXT = 270 ω.μm. These MOSFETs operate within 20% of the ballistic limit for LEFF ≤ 30 nm and are among the best In0.53Ga0.47As FETs in literature. We investigate the effects of channel/barrier doping on FET performance and show that increase in mobility beyond ∼ 500 cm2/Vs has progressively smaller impact as LEFF is scaled down. Our self-aligned MOSFETs were fabricated using a CMOS-compatible process flow that includes gate and spacer formation using RIE, source/drain extension (SDE) implantation, and in-situ-doped raised source/drain (RSD) epitaxy. This process flow is manufacturable and easily extendable to non-planar architectures.