Vertical furnace and a method for operating the same

A method for operating a vertical furnace constructed and arranged with a reaction chamber for depositing a molybdenum nitride layer on a plurality of wafers in the reaction chamber, the method comprising a molybdenum nitride depositing run for depositing the molybdenum nitride layer;

• and a cleaning run for cleaning the reaction chamber, the molybdenum nitride deposition run comprising:
• providing a plurality of wafers in a wafer boat with a wafer handler and loading the wafer boat with a boat loader in a substantial vertical direction into the reaction chamber;
• heating a wall of the reaction chamber;
• flowing a molybdenum precursor into the reaction chamber;
• flowing a nitrogen precursor into the reaction chamber to deposit molybdenum nitride on the wafers in the wafer boat;
• and,
• removing the plurality of wafers in the wafer boat from the reaction chamber;
• wherein the cleaning run comprises flowing a cleaning gas to the reaction chamber to remove deposited layers in the reaction chamber and the cleaning run is ran every 1 to 10 molybdenum nitride deposition runs.