| 摘要 |
A method of manufacturing a semiconductor device comprising a buried channel field effect transistor, which method comprises the formation of a stack of layers on a substrate (1) with an active semiconductor layer (13, 14) having a non-zero aluminium (Al) content, a semiconductor cap layer (4) without aluminium (Al), a masking layer (100) provided with a gate opening (51); a first selective etching step by means of a fluorine (F) compound in the cap layer (4) down to the upper surface (22) of the active layer (13, 14) on which a stopper layer (3) of aluminum fluoride (AlF3) is automatically formed; removal of said stopper layer (3) and covering of the region of the first transistor (T) with a material (200) which can be removed without deterioration of the masking layer (100); a second, non-selective etching step in the active layer (13, 14) down to a depth (62E) equal to the difference (HE-HD) in depth between the gate recesses (52D, 52E) of the two transistors; removal of the covering material (200); and a third, non-selective etching step in the active layer (13, 14) simultaneously for the two transistors (D, E) down to the bottom level (42D) of the gate recess of the first transistor (D).
|
