Abstract:
A high density plasma deposition process for eliminating or reducing a zipper-like profile of opened-up voids in a poly trench fill by controlling separation between a transfer gate and storage node in a vertical DRAM, comprising: etching a recess or trench into poly Si of a semiconductor chip; forming a pattern of SiN liner using a mask transfer process for formation of a single sided strap design; removing the SiN liner and etching adjacent collar oxide away from a top part of the trench; depositing a high density plasma (HDP) polysilicon layer in the trench by flowing either SiH4 or SiH4 + H2 in an inert ambient; employing a photores ist in the trench and removing the high density plasma polysilicon layer from a top surface of the semiconductor to avoid shorting in the gate conductor either by spinning on resist and subsequent chemical mechanical polishing or chemical mechanical downstream etchback of the polysilicon layer; and stripping the photoresist and depositing a top trench oxide by high density plasma.
Abstract:
Methods forming a trench region of a trench capacitor structure having increase surface area are provided. One method includes the steps of forming a discontinuous polysilicon layer (43) on exposed walls of a lower trench region, the discontinuous polysilicon layer having gaps (44) therein which expose portions of said substrate; oxidizing the lower trench region such that the exposed portions of said substrate provided by the gaps in the discontinuous polysilicon layer are oxidized into oxide material which forms a smooth and wavy layer with the discontinuous polysilicon layer; and etching said oxide material so as to form smooth hemispherical grooves (46) on the walls of the trench region.
Abstract:
A process for fabricating a single-sided semiconductor deep trench structure filled with polysilicon trench fill material includes the following steps. Form a thin film, silicon nitride, barrier layer over the trench fill material. Deposit a thin film of an amorphous silicon masking layer over the barrier layer. Perform an angled implant into portions of the amorphous silicon masking layer which are not in the shadow of the deep trench. Strip the undoped portions of the amorphous silicon masking layer from the deep trench. Then strip the newly exposed portions of barrier layer exposing a part of the trench fill polysilicon surface and leaving the doped, remainder of the amorphous silicon masking layer exposed. Counterdope the exposed part of the trench fill material. Oxidize exposed portions of the polysilicon trench fill material, and then strip the remainder of the masking layer.