摘要 |
An insulated-gate field-effect transistor (500, 510, 530, or 540) has a hypoabrupt step-change vertical dopant profile below one (104 or 564) of its source/drain zones for reducing the parasitic capacitance along the pn junction between that source/drain zone and adjoining body material (108 or 568). In particular, the concentration of semiconductor dopant which defines the conductivity type of the body material largely undergoes a step increase by at least a factor of 10 in moving from that source/drain zone down to an underlying body-material location no more than 10 times deeper below the upper semiconductor surface than that source/drain zone. |