We have developed a new method of silicon digital epitaxy, shot gas epitaxy, in which the dose of the source gas molecules per pulse, (shot), is easily controlled by charging and emptying a gas-charge cell. What distinguishes this method from conventional atomic layer epitaxy, lies in its ability to vary the grown thickness per cycle. The grown film thickness per cycle is highly temperature dependent below 750-degrees-C while it is temperature independent above it. The unit thickness in the latter region is also predicted to be varied by changing the dose per pulse from the similarity of the growth mode to that of gas-source molecular beam epitaxy.