公开(公告)号：EP1911098A1

公开(公告)日：2008-04-16

申请号：EP05767906.0

申请日：2005-06-30

申请人： Freescale Semiconductor, Inc.

发明人： SPARKS, Terry

IPC分类号： H01L29/786 ,  H01L21/336 ,  H01L21/3213 ,  H01L21/764

CPC分类号： H01L29/78639 ,  H01L21/32135 ,  H01L21/84 ,  H01L29/66772 ,  H01L29/78654

摘要： A method of forming a semiconductor structure comprises forming a first layer of silicon (10) and then forming a second, silicon germanium, layer (12) adjacent the silicon layer (10). A thin third layer of silicon (14) is then formed adjacent the second layer (12). A gate structure is then formed upon the third layer of silicon (14) using convention Complementary Metal Oxide Semiconductor (CMOS) processes. Trenches are then formed into the second layer (12) and the structure is then exposed to a thermal gaseous chemical etchant, for example heated hydrochloric acid. The etchant removes the silicon germanium, thereby forming a Silicon-On­-Nothing structure. Thereafter, conventional CMOS processing techniques are applied to complete the structure as a Metal Oxide Semiconductor Field Effect Transistor, including the formation of spacer walls (28) from silicon nitride, the silicon nitride (30) also filling a cavity formed beneath the third layer of silicon (14) by removal of the silicon germanium.