Trench-gate semiconductor devices having a channel-accommodating region and their methods of manufacture

Abstract

Compact trench-gate semiconductor devices, for example a cellular power MOSFET with sub-micron pitch (Yc), are manufactured with self-aligned techniques that use sidewall spacers (52) in different ways. Thereby, the source region (13) and a contact window (18a) for a source electrode (33) can be self-aligned to a narrow trench (20) containing the trench-gate (11). Thereby, the channel-accommodating region (15) can also be provided after forming the trench-gate (11), and with very good control of its doping concentration (Na; p) adjacent to the trench (20). To achieve this control, its dopant is provided after removing the spacers (52) from the mask (51) so as to form a doping window (51b), which may also be used for the source dopant, adjacent to the trench-gate (11). A high energy dopant implant (61) or other doping process provides this channel dopant adjacent to the trench (20) and extending laterally below the mask (51,51n). A remarkably uniform doping profile can be achieved beneath the doping window (51b) and beneath the mask (51,51n). By using a high ion energy and high dose, the dopant ions (61) at the doping window (51b) can be laterally scattered below the mask (51) while those at the mask (51) penetrate there-through to be implanted in the underlying portion of the body (100).

Dependencies are inferred from the claim text.