silicon nitride film is even enhanced after the rapid annealing the improved device properties obtained by using the disclosed fabrication method are explained as follows fig5 shows the nature of pmos devices it is seen that the silicon nitride layer with ion implantation can effectively enhance its output properties fig6 shows the gain of the semiconductor device finished using the disclosed method it is seen that the gain of the nmos device with a silicon nitride cap layer can be greatly enhanced the nature modification of an nmos device is shown in fig7 the current of the nmos with a silicon nitride cap layer is largely improved fig8 shows the relation between the gain of an nmos device with a silicon nitride cap layer and the gate length it is seen that the gain increases as the gate length decreases the disclosed manufacturing method provides a process integration technique to improve the cmos device properties the invention uses back side stress engineering to change the stress values the cmos according to the disclosed method does not necessarily need the use of a silicide process the silicon dioxide film can be undoped the disclosed manufacturing method allows the silicon nitride film to be directly stacked on the mos device without first depositing a layer of oxide with the deposition of silicon nitride and silicon dioxide layers different regions can have tensile or compressive stresses by further employing ion implantation this is completely different from the prior art where film depositions depend on which type of mos pmos or.