Chemical vapor deposition methods, and atomic layer deposition method

An atomic layer deposition method comprising:

• positioning a semiconductor substrate within an atomic layer deposition chamber;
• feeding a first deposition precursor gas through an inlet valve to an inlet of a variable volume accumulator reservoir, an outlet valve from the variable volume accumulator reservoir being closed during said feeding;
• and
• with the first deposition precursor gas therein, closing the inlet valve, opening the outlet valve and decreasing volume of the variable volume accumulator reservoir effective to expel first deposition precursor gas therefrom through the outlet valve and into the chamber under conditions effective to deposit a layer on the substrate.

A chemical vapor deposition method comprising:

• positioning a semiconductor substrate within a deposition chamber;
• feeding a first deposition precursor gas to an inlet of a variable volume accumulator reservoir, the feeding occurring from a gas passageway through the inlet to the variable volume accumulator reservoir, and further comprising maintaining pressure within the gas passageway proximate the inlet and pressure within the variable volume accumulator reservoir substantially constant during said feeding;
• and
• with the first deposition precursor gas therein, decreasing volume of the variable volume accumulator reservoir effective to expel first deposition precursor gas therefrom into the chamber under conditions effective to deposit a layer on the substrate, the expelling occurring through an outlet of the variable volume accumulator reservoir into the gas passageway from the variable volume accumulator reservoir, and further comprising maintaining pressure within the gas passageway proximate the outlet and pressure within the variable volume accumulator reservoir substantially constant during said decreasing.

A chemical vapor deposition method comprising:

• positioning a semiconductor substrate within a deposition chamber;
• feeding a first deposition precursor gas through an inlet valve to an inlet of a variable volume accumulator reservoir, an outlet valve from the variable volume accumulator reservoir being closed during said feeding, said feeding providing a first volume of the first deposition precursor gas within the variable volume accumulator reservoir at a first pressure;
• after providing the first volume of the first deposition precursor gas within the variable volume accumulator at the first pressure, closing the inlet valve;
• with the inlet and outlet valves closed, reducing the first volume of the first deposition precursor gas within the variable volume accumulator reservoir effective to increase the pressure to a second pressure;
• and
• after the reducing, opening the outlet valve and decreasing volume of the variable volume accumulator reservoir effective to expel first deposition precursor gas therefrom through the outlet valve at an outlet pressure exceeding the first pressure and into the chamber under conditions effective to deposit a layer on the substrate.