Forming a partially depleted SOI MOSFET structure and method of test

Testing a partially depleted SOI MOSFET structure and method of forming, the test structure comprising: testing the MOSFET, a plurality of test contact areas, and the first isolation structure. Test MOSFET comprising: SOI semiconductor substrate having a top silicon layer; located on the top of the T-shaped gate above the silicon, including the "a" type part and "|" type portion; source region is located within the top silicon layer, the drain region and the body contact region . A plurality of test contact areas along the "|" directional extension portion spaced and located away from the source region "|" type inner side of the top silicon portion. Depth of the first isolation structure is not less than the thickness of the top silicon layer and located between the two contact regions adjacent to the test. With this test structure to be measured can be indirectly detected potential local MOSFET body region a body region in different positions, to find help avoid critical channel dimension MOSFET floating body effect, in order to further optimize the structure of the MOSFET.