摘要:
A method for increasing the surface area of an original surface in a semiconductor device is disclosed. In an exemplary embodiment of the invention, the method includes forming a layered mask upon the original surface, the layered mask including a masking layer thereatop having a varying thickness. An isotropic etch is then applied to the layered mask, which isotropic etch further removes exposed portions of the original surface as the layered mask is removed. Thereby, the isotropic etch enhances the non-uniformity of the masking layer and creates a non-uniformity in planarity of the original surface.
摘要:
In a process for making a DT DRAM structure, the improvement of providing a surface area enhanced DT below the collar region and node capacitance that does not shrink with decreasing groundrule/cell size, comprising: a) providing a semiconductor substrate having a collar region and an adjacent region below the collar region, the collar region having SiO deposited thereon; b) depositing a SiN liner on said collar region and on the region below the collar; c) depositing a layer of a-Si on the SiN liner to form a micromask; d) subjecting the structure from step c) to an anneal/oxidation step under a wet environment at a sufficient temperature to form a plurality of oxide dot hardmasks; e) subjecting the SiN liner to an etch selective to SiO; f) subjecting the structure from step e) to a Si transfer etch using a chemical dry etch (CDE) selective to SiO to create rough Si surface; g) stripping SiO and the SiN; and forming a node and collar deposition.
摘要:
Semiconductor devices having deep trenches with fill material therein having low resistivity are provided along with methods of fabricating such semiconductor devices.
摘要:
A method for forming substantially uniformly thick, thermally grown, silicon dioxide material on a silicon body independent of bon axis. A trench is formed in a surface of the silicon body, such trench having sidewalls disposed in different crystallographic planes, one of such planes being the crystallographic plane and another one of such planes being the plane. A substantially uniform layer of silicon nitride is formed on the sidewalls. The trench, with the with substantially uniform layer of silicon nitride, is subjected to a silicon oxidation environment with sidewalls in the plane being oxidized at a higher rate than sidewalls in the plane producing silicon dioxide on the silicon nitride layer having thickness over the plane greater than over the plane. The silicon dioxide is subjected to an etch to selectively remove silicon dioxide while leaving substantially un-etched silicon nitride to thereby remove portions of the silicon dioxide over the plane and to thereby expose underlying portions of the silicon nitride material while leaving portions of the silicon dioxide over the plane on underlying portions of the silicon nitride material. Exposed portions of the silicon nitride material are selectively removed to expose underlying portions of the sidewalls of the trench disposed in the plane while leaving substantially un-etched portions of the silicon nitride material disposed on sidewalls of the trench disposed in the plane. The structure is then subjected to an silicon oxidation environment to produce the substantially uniform silicon dioxide layer on the sidewalls of the trench.
摘要:
A system and method of forming an electrical connection (142) to the interior of a deep trench (104) in an integrated circuit utilizing a low-angle dopant implantation (114) to create a self-aligned mask over the trench. The electrical connection preferably connects the interior plate (110) of a trench capacitor to a terminal of a vertical trench transistor. The low-angle implantation process, in combination with a low-aspect ratio mask structure, generally enables the doping of only a portion of a material overlying or in the trench. The material may then be subjected to a process step, such as oxidation, with selectivity between the doped and undoped regions. Another process step, such as an etch process, may then be used to remove a portion of the material (120) overlying or in the trench, leaving a self-aligned mask (122) covering a portion of the trench, and the remainder of the trench exposed for further processing. Alternatively, an etch process alone, with selectivity between the doped and undoped regions, may be used to create the mask. The self-aligned mask then allows for the removal of selective portions of the materials in the trench so that a vertical trench transistor and a buried strap may be formed on only one side of the trench.
摘要:
A method of forming a vertically-oriented device in an integrated circuit using a selective wet etch to remove only a part of the sidewalls in a deep trench, and the device formed therefrom. While a portion of the trench perimeter (e.g., isolation collar 304) is protected by a mask (e.g., polysilicon 318), the exposed portion is selectively wet etched to remove selected crystal planes from the exposed portion of the trench, leaving a flat substrate sidewall (324) with a single crystal plane. A single side vertical trench transistor may be formed on the flat sidewall. A vertical gate oxide (e.g. silicon dioxide 330) of the transistor formed on the single crystal plane is substantially uniform across the transistor channel, providing reduced chance of leakage and consistent threshold voltages from device to device. In addition, trench widening is substantially reduced, increasing the device to device isolation distance in a single sided buried strap junction device layout.
摘要:
A method for forming substantially uniformly thick, thermally grown, silicon dioxide material on a silicon body independent of axis. A trench is formed in a surface of the silicon body, such trench having sidewalls disposed in different crystallographic planes, one of such planes being the crystallographic plane and another one of such planes being the plane. A substantially uniform layer of silicon nitride is formed on the sidewalls. The trench, with the substantially uniform layer of silicon nitride, is subjected to a silicon oxidation environment with sidewalls in the plane being oxidized at a higher rate than sidewalls in the plane producing silicon dioxide on the silicon nitride layer having thickness over the plane greater than over the plane. The silicon dioxide is subjected to an etch to selectively remove silicon dioxide while leaving substantially un-etched silicon nitride to thereby remove portions of the silicon dioxide over the plane and to thereby expose underlying portions of the silicon nitride material while leaving portions of the silicon dioxide over the plane on underlying portions of the silicon nitride material. Exposed portions of the silicon nitride material are selectively removed to expose underlying portions of the sidewalls of the trench disposed in the plane while leaving substantially un-etched portions of the silicon nitride material disposed on sidewalls of the trench disposed in the plane. The structure is then subjected to an silicon oxidation environment to produce the substantially uniform silicon dioxide layer on the sidewalls of the trench.
摘要:
A method of using at least two insulative layers to form the isolation collar of a trench device, and the device formed therefrom. The first layer is preferably an oxide (e.g., silicon dioxide 116) formed on the trench substrate sidewalls, and is formed through a TEOS, LOCOS, or combined TEOS/LOCOS process. Preferably, both the TEOS process and the LOCOS process are used to form the first layer. The second layer is preferably a silicon nitride layer (114) formed on the oxide layer. The multiple layers function as an isolation collar stack for the trench. The dopant penetration barrier properties of the second layer permit the dielectric collar stack to be used as a self aligned mask for subsequent buried plate (120) doping.
摘要:
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.
摘要:
The vertical DRAM capacitor with a buried LOCOS collar characterized by: a self-aligned bottle and gas phase doping; no consumption of silicon at the depth of the buried strap; no reduction of trench diameter; and a nitride layer to protect trench sidewalls during gas phase doping.