Film forming method and film forming apparatus

A film forming apparatus comprising:

• a processor;
• and
• a controller, wherein
• the controller is configured to control the processor to execute:
• forming a silicon germanium film on a substrate by supplying a first silicon-containing gas and a germanium-containing gas to the substrate while heating the substrate at a first temperature;
• forming a first silicon film on the silicon germanium film by supplying a second silicon-containing gas to the substrate while heating the substrate at the first temperature;
• increasing a temperature of the substrate from the first temperature to a second temperature higher than the first temperature;
• and
• forming a second silicon film on the first silicon film by supplying a third silicon-containing gas to the substrate while heating the substrate at the second temperature.