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;
• feeding a first precursor gas to the semiconductor substrate within the chamber to form a first discrete monolayer on the semiconductor substrate;
• feeding a first inert purge gas to the semiconductor substrate within the chamber to react with the first precursor gas which has not formed the first discrete monolayer on the semiconductor substrate;
• feeding a second precursor gas to the chamber to react with the first precursor gas which has formed the first discrete monolayer, thereby forming discrete atomic size islands;
• after purging by the first inert purge gas, a uniform or non-uniform first monolayer is formed in a monoatomic discrete distribution;
• feeding a second inert purge gas to the semiconductor substrate within the chamber to remove the second precursor gas which has not reacted with the first precursor gas and byproducts produced by the reaction between the first and the second precursor gases;
• and
• forming a dielectric layer to fill spaces between the discrete atomic size islands and cover the discrete atomic size islands on the semiconductor substrate.