Abstract: A buried channel vertical double-diffusion MOS (buried channel VDMOS) device comprising a substrate, a drain region, a gate region, a source region and a channel region. The drain region is located above the substrate and the gate region is above the substrate surface. The source region is located between two neighboring gates in the substrate. The channel region is located above the drain region separated from the gate by a gate-insulating layer. The channel region further includes a main region, a buried channel region, a first region and a second region. The buried channel region is located below the gate-insulating layer. The buried channel region is impurity-doped so that the threshold voltage of the buried channel VDMOS device can be adjusted. The first region is located in the substrate between two neighboring gates, next to the drain region with portion of it extending into the region underneath the gate.

Abstract: A fabrication method for shallow trench isolation (STI) is briefly described as follows. A substrate is provided with a patterned mask layer and pad oxide layer formed thereon, so that a first opening, which exposes a part of the substrate, is formed. A shallow trench is then formed in the substrate, followed by filling the shallow trench with a first insulating layer, wherein the surface of the first insulating layer is lower than the surface of the substrate, and a part of the substrate forming the sidewall of the shallow trench is exposed. A part of the mask layer and pad oxide layer is removed to enlarge the first opening, so that a second opening, which exposes a part of the substrate, is formed. A doped region is formed on the exposed part of the substrate, while the second opening and the shallow trench are filled with a second insulating layer. Finally, the mask layer and the pad oxide layer are removed in sequence to complete the manufacture of the STI.

Abstract: A method of fabricating a lower electrode of a capacitor. A sacrificial multilayer is formed on a semiconductor layer. The sacrificial multi-layer is a stack of alternating first and second sacrificial layers. A patterned first mask layer having a first opening above a conductive plug in the semiconductor substrate is formed on the sacrificial multi-layer. A planar spacer is formed on the sidewall of the first opening. A second mask layer is formed to fill the first opening. The planar spacer and the sacrificial multi-layer thereunder are anisotropically etched until the semiconductor substrate is exposed to form a second opening while using the first mask layer and second mask layer as a mask. The first sacrificial layers exposed by the second opening are isotropically etched to form a plurality of recesses. The second opening and the recesses are filled with a conductive material layer. Finally, the first mask layer, second mask layer, and sacrificial multi-layer are removed.

Abstract: A method of fabricating a dynamic random-access memory (DRAM) device integrates a shallow trench isolation (STI) process and a storage node process into the fabrication of the DRAM device. With a bit line over capacitor (BOC) structure, the capacitor is laid out in parts of the shallow trench isolation structure to increase the surface area of the storage node by using the trench. During the fabrication of the capacitor, a stacked plug used to connect the bit line is formed. The stacked plug used as the interconnection in the circuit region is also formed. An insulating layer is formed to cover the capacitor, and an opening is formed therein to expose the stacked plug. A bit line and an interconnection are formed on the insulating layer to connect with a conducting layer which is located in the stacked plug and contacted with the source/drain regions.