Method for forming doped regions on an SOI device
 An SOI layer has a dielectric layer and a silicon layer formed on the dielectric layer. A shallow trench isolation structure is formed on the silicon layer. The STI structure passes through to the dielectric layer. A thermal diffusion process is performed to drive dopants into a first region of the silicon layer so as to form an N-well or P-well doped region. Next, a thermal diffusion process is performed to drive dopants into a second region of the silicon layer so as to form a P-well or N-well doped region. Finally, an epitaxy layer, having a thickness of about 200 angstroms, is grown on the surface of the silicon layer by way of a molecular-beam epitaxy (MBE) growth process, a liquid-phase epitaxy (LPE) growth process, or a vapor-phase epitaxy (VPE) growth process. 
United Microelectronics Corp.
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inventional inventional
Wen-Kuan Hua-Chou Jiann
Yeh Tseng Liu