The optimized values for the physical and ge-ometrical parameters of the p-and n-regions used in the voltage-sustaining layer of the COLMOSTM2 are presented. Design of the parameters aimed to produce the lowest specific on-resistance. Ron.for a given breakdown vnltage. Vp.A new relationship between the Ron and Vv for the COOLMOSTM IS developed as Ron=cv1.32, where the constant Cis dependent by putting a thin layer of insulator between the p-region and its neighboring n-regions, the value of Ron can be further reduced. The possibilry of incorporating the insulating layer may open up opportunities for practical implementation of the COOLMOSTM fof volume production.