Method of manufacturing semiconductor device, substrate processing apparatus, and recording medium

A substrate processing apparatus, comprising:

• a process chamber in which a substrate is accommodated;
• a supply system configured to supply a first process gas containing silicon or germanium and containing a halogen element, a second process gas containing silicon and not containing a halogen element, a third process gas containing germanium and not containing a halogen element and a fourth process gas containing germanium and not containing a halogen element to the substrate accommodated in the process chamber;
• and
• a controller configured to control the supply system to perform inside the process chamber:
• forming a first seed layer containing silicon and germanium on the substrate by performing, a predetermined number of times, a cycle which includes supplying the first process gas to the substrate, supplying the second process gas to the substrate, and supplying the third process gas to the substrate;
• and
• forming a germanium-containing film on the first seed layer by supplying the fourth process gas to the substrate.