n type ions are injected into the pbody area 209 a and the n type grade area 210 in the n epitaxial layer of the ldmos transistor area i along the source and drain patterns using the tenth photoresist layer as a mask to form a source s in the pbody area 209 a and a drain d in the n type grade area 210 and n type ions are injected into the pbody area 209 b and the nsink area 212 in the n epitaxial layer of the vdmos transistor area ii to form a source s in the pbody area 209 b and a drain d in the nskin area 212 in the present embodiment the n type ions injected to form the sources s and the drains d are arsenic ions the ions are injected at a dosage of 4 u00d7 1015 cm2 and energy of 80 kev further referring to fig1 an eleventh photoresist layer not illustrated is formed on the n epitaxial layer the local oxidation of silicon locos isolation area 204 and the gates 208 a and 208 b after the tenth photoresist layer is removed and a p area pattern is defined in the ldmos transistor area i after the.