Atomic layer deposition method and semiconductor device formed by the same

An atomic layer deposition method, comprising the steps of:

• placing a semiconductor substrate in an atomic layer deposition chamber;
• flowing a first precursor gas to the semiconductor substrate within the atomic layer deposition chamber to form a first discrete monolayer on the semiconductor substrate;
• flowing an inert purge gas to the semiconductor substrate within the atomic layer deposition chamber to remove the first precursor gas which does not form the first monolayer on the semiconductor substrate;
• flowing a second precursor gas to the atomic layer deposition chamber to react with the first precursor gas which forms the first monolayer, thereby forming a first discrete compound monolayer;
• flowing an inert purge gas to the semiconductor substrate within the atomic layer deposition chamber to remove the second precursor gas which does not react with the first precursor gas and a byproduct of the reaction between the first and the second precursor gases;
• forming a first dielectric layer to cover the first discrete compound monolayer on the semiconductor substrate, wherein the first dielectric layer is made of silicon oxide;
• flowing a third precursor gas to the atomic layer deposition chamber to form a third discrete monolayer above first dielectric layer;
• flowing an inert purge gas to the atomic layer deposition chamber to remove the third precursor gas which does not form the third monolayer with the first dielectric layer;
• flowing a fourth precursor gas to the atomic layer deposition chamber to react with the third precursor gas which has formed the third monolayer, thereby forming a second discrete compound monolayer;
• flowing an inert purge gas to the atomic layer deposition chamber to remove the forth precursor gas which does not react with the third monolayer and a byproduct of the reaction between the third and the forth precursor gases;
• and
• forming a second dielectric layer to cover the second discrete compound monolayer above the first dielectric layer.