A new tool for in situ x-ray photoelectron spectroscopy (XPS) analysis of the atomic layer chemical vapor deposition (ALCVD) process has been developed. Monitoring of the growth process is achieved by interconnecting an ALCVD reactor with an XPS analyzer. A basic experiment demonstrates the first in situ collected XPS data from the surface of each monoatomic layer of ZnO deposited in the ALCVD process. The method is able to resolve chemical changes as sequential layers evolve on the surface and will reveal critical parameters for the ALCVD process to work. Quantitative analysis of our results confirms the ALCVD theory.