We have investigated the atomic layer deposition (ALD) on SiO 2 and III-V (ie, In 0.53 Ga 0.47 As) substrates of Al-doped ZrO 2 (Al-ZrO 2) films. The aim is to benefit from trimethylaluminum-based chemistry as adopted in the ALD of Al 2 O 3 while concomitantly obtaining an improvement in the value of the dielectric constant of the gate stack. An in situ monitoring of the process with spectroscopic ellipsometry was carried out in order to address the formation of the first few monolayers of the films. The correlation with the structural and chemical characterization provides insights about the interface composition upon ALD. A k value of 19±2 is demonstrated for Al-ZrO 2 films deposited on SiO 2. The electrical performances of capacitors fabricated on In 0.53 Ga 0.47 As including Al-ZrO 2 as gate dielectric exhibit encouraging properties compared to those acquired for Al 2 O 3. However, a further optimization of the …