Aluminum sulfide is a promising material for energy storage, photonics, and microelectronics applications. Most of these applications require thin films with a high control over layer thickness and composition making atomic layer deposition an ideal deposition technique. The authors report a plasma enhanced process for aluminum sulfide based on trimethylaluminum and H2S-plasma. The growth characteristics were studied using in situ spectroscopic ellipsometry, indicating linear growth at a rate of 1.2 angstrom/cycle at 90 degrees C. Self-saturated growth could be achieved in a temperature window ranging from 90 to 350 degrees C. The process relies on combustion reactions during the plasma step, as confirmed by the observation of CS2 using in situ mass spectrometry measurements. Ex situ x-ray photoelectron spectroscopy, x-ray diffraction, and scanning electron microscopy/energy-dispersive x-ray spectroscopy measurements showed that the deposited layers are amorphous and pinhole free.