Abstract: A method for electrochemical local oxidation of silicon of selected regions of a silicon substrate of a semiconductor wafer avoids the formation of bird's beak structures of the prior art. The method involves the initial formation of a patterned generally nonconductive layer such as silicon nitride on a silicon substrate of a semiconductor wafer. The semiconductor wafer is then immersed in a bath of oxidizing electrolyte solutions such as pure water, acid, or ammonium. While immersed, the semiconductor wafer is subjected to an electrical field. The electrical field is created by connecting a power source both to a cathode located within the bath and to the semiconductor wafer, thereby employing the semiconductor wafer as an anode. The electrical field causes the oxygen of the bath to react with the silicon substrate and form patterned oxide regions in the locations where the silicon substrate was left unmasked by the patterned generally non-conductive layer.

Abstract: A method for forming an isolating layer in a semiconductor device includes the steps of forming a first material layer on an active layer having a major axis and a minor axis, forming a second material layer in a form of sidewall at sides of the first material layer in a direction of the major axis, and conducting field oxidation using the first and second material layers as masks to form the isolating layer.

Abstract: A semiconductor processing method of providing a polysilicon film having induced outer surface roughness includes, a) providing a polysilicon layer over a substrate, the polysilicon layer having an outer surface of a first degree of roughness; b) providing a layer of a refractory metal silicide over the outer surface of the polysilicon layer, the refractory metal silicide preferably being WSi.sub.x where "x" is initially from 1.0 to 2.5, the WSi.sub.x layer and the polysilicon layer outer surface defining a first interface therebetween; c) annealing the substrate at a temperature and for a time period which are effective to transform the WSi.sub.x into a tetragonal crystalline structure and to transform the first interface into a different second interface, the WSi.sub.x layer not being in a tetragonal crystalline state prior to the anneal, the WSi.sub.x at the second interface having an increased value of "x" from the initial value of "x"; and d) etching the WSi.sub.

Abstract: CMOS transistors are formed by a damascene process resulting in field oxide regions exhibiting essentially no bird's beak portions. A trench isolation is also formed in a source/drain region each transistor between adjacent junctions.

Abstract: The present invention relates to a method of fabricating a CMOS transistor which can further reduce the size of a chip since it is not necessary to consider the metal contact process margin since a gate electrode of a PMOS transistor and a gate electrode of an NMOS transistor are directly connected with a polysilicon wiring during a process of forming the gate electrodes, which can prevent the formation of a parasitic transistor by forming a cell space region in an active region below the polysilicon wiring.

Abstract: A process is described for forming a heavily doped buried element below an active device region of a silicon wafer without the use of costly epitaxial layers and without incurring ion implantation damage within active device regions. The method is particularly applicable to active device regions which have small lateral dimensions. Thus, the technological trend towards shrinking devices favors the incorporation of the process of the invention. The process utilizes a silicon nitride hardmask to define a narrow band around the perimeter of the device active area. A deep implant is performed through this mask, placing a ring of dopant below and outside the active area. The silicon nitride hardmask is then patterned a second time to define the conventional field oxide isolation regions. The LOCOS field oxidation is then performed whereby the implanted dopant diffuses vertically, engaging the field oxide around the perimeter of the device region and laterally filling in the region under the device active area.

Abstract: A CMOS process with inverse-T gate LDD structure uses liquid phase deposition (LPD) processes to achieve a low thermal budget with only six photoresist-masks in a CMOS device. A first photoresist-mask is used to form field oxide regions. A second photoresist-mask is used to implant a P-well. Before the second photoresist-mask is removed, a first LPD oxide layer is used to cover the N-well. The second photoresist-mask is removed, and the first LPD oxide layer is used as a mask for implanting the N-well. The first LPD oxide layer is removed and a polysilicon layer is deposited on the substrate. A third photoresist-mask is used to etch the polysilicon layer to form gate-structures for the NMOS and PMOS devices. A conformal amorphous Si layer is formed on the gate-structures, followed by forming a fourth photoresist-mask over the N-well. A conformal LPD oxide layer is formed on the conformal polysilicon layer over the P-well. N-LDD regions are then implanted.

Abstract: A process for reducing stress during processing of semiconductor wafers comprising the steps of depositing a masking stack on a top and a bottom surface of the wafer and then removing at least a portion of the masking stack on the bottom surface prior to forming isolation regions on the top surface of the semiconductor wafer. In one embodiment, silicon nitride is formed on the top and the bottom surface of a silicon wafer. The silicon nitride is then patterned and etched on the top surface of the wafer to expose regions of the underlying silicon for field oxide formation. Prior to the field oxidation formation on the top side of the wafer, the silicon nitride layer on the bottom side of the wafer is removed so that a layer of silicon dioxide is formed on the bottom surface of the wafer during field oxidation formation.

Abstract: A method of manufacturing a semiconductor device comprises; forming a device isolation region in a semiconductor substrate; forming at least a first conductivity type impurity region in the semiconductor substrate; and forming on the semiconductor substrate a transistor including a gate insulating film, a gate electrode, source/drain regions and a channel located directly under the gate electrode, wherein the first conductivity type impurity region is formed by the steps of: an ion implantation 1 having a concentration peak at a location deeper than the bottom of the device isolation region; an ion implantation 2 having a concentration peak at a location around the bottom of the device isolation region; an ion implantation 3 having a concentration peak around the junction regions where the source/drain regions are to be formed; and an ion implantation 4 having a concentration peak on the surface or directly under the surface of the region where the channel is to be formed.

Abstract: A method of fabricating alignment marks on an integrated circuit device including steps of: forming first pad oxide layer and first nitride layer on a P-type semiconductor substrate; coating and patterning first photoresist layer by lithography; partially etching first nitride layer to form first nitride pattern by first photoresist etching mask; and ion implanting N-type ions to form an N-doped region; coating and patterning second photoresist layer by lithography; partially etching first nitride pattern to form second nitride pattern; and ion implanting P-type ions to formed a P-doped region. Next, performing thermally drive in N-type and P-type impurities to form N-well and P-well regions, and growing an oxide layer simultaneously. Finally, the height difference between the oxide layer and the second nitride pattern producing a ladder topography can be used as an alignment mark for the succeeding lithographic processes.

Abstract: The present invention develops a process for forming dual conductive wells in a silicon substrate for an integrated circuit by: forming an oxide layer on the silicon substrate; patterning an oxidation barrier layer on the oxide layer, thereby defining active areas for active devices; introducing first p-type conductive impurities into the silicon substrate thereby forming at least one p-type conductively doped well region; masking over the p-type conductively doped well region; introducing n-type conductive impurities into the silicon substrate thereby forming at least one n-type conductively doped well region; removing the masking; forming oxide regions in areas not covered by the patterned oxidation barrier layer; and forcing the p-type and n-type conductive impurities further into the silicon substrate thereby forming the dual well regions, the well regions having adequate conductive depth to provide for the formation of the active devices.

Abstract: A method of forming first and second conductivity type wells in a semiconductor device includes the steps of forming an isolation layer on a semiconductor substrate, forming a multi-layer mask over a portion of the substrate to define the first and second conductivity type wells, implanting a first conductivity type impurity to form the first conductivity type well, removing a partial layer from the multi-layer mask, and implanting a second conductivity type impurity to form the second conductivity type well.

Abstract: A semiconductor device includes at least one passive device and is configured such that parasitic capacitances associated with the passive device are minimized. A substrate layer of the semiconductor device is formed of a substrate material characterized by a first dielectric constant. The substrate layer has at least one deep trench formed therein, and the deep trench is filled with a trench fill material characterized by a second, effective, dielectric constant that is lower than the first dielectric constant. A field layer is formed on a surface of the substrate layer over the deep trench. Finally, the passive device is formed on a surface of the field layer.

Abstract: A process for reducing the severe topography in field oxide regions, via use of insulator spacers, on the sides of the field oxide region, has been developed. An insulator layer is first deposited on a field oxide region, and on the active device region, between the isolating field oxide regions. An anisotropic RIE procedure is next employed to create insulator spacers, on the sides of the field oxide regions. The insulator spacers reduce the severity of the field oxide regions, reducing the risk of polysilicon residuals and unwanted sidewalls, during the patterning process used to create the polysilicon gate structure.

Abstract: The invention is a process for filling narrow isolation trenches with thermal oxide using a nitride spacer and a second trench etch. The method begins by providing forming a pad oxide layer 20 and a first nitride layer 30 over a substrate. A first opening is formed in the pad oxide layer 20 and first nitride layer 30. The substrate is then etched through the first opening forming a first trench 40 in the substrate. A thin oxide film 50 is then grown over the substrate in the bottom and sidewalls of the first trench 40. Nitride spacers 60 are grown over the sidewalls of the first trench and over the thin oxide layer 40 on the sidewalls of the trench. A portion of the thin oxide film 50 on the bottom of the trench is etched. The substrate in the bottom of the first trench is etched forming a second trench 70. The etch exposes portions of the substrate on the bottom of the deeper second trench.

Abstract: A new method of forming an integrated circuit MNOS/MONOS device with suppressed off-cell leakage current is described. A silicon oxide layer is formed on the surface of a semiconductor substrate. A layer of silicon nitride is deposited over the silicon oxide layer and patterned. A first ion implantation is performed at a tilt angle to form channel stop regions in the semiconductor substrate not covered by the patterned silicon nitride layer wherein the channel stop regions partially extend underneath the patterned silicon nitride layer. The silicon substrate not covered by the patterned silicon nitride layer is oxidized to form field oxide regions within the silicon substrate wherein the channel stop regions extend under the full length of the field oxide regions. The patterned silicon nitride layer is removed. An insulating layer of silicon nitride/silicon oxide (NO) or silicon oxide/silicon nitride/silicon oxide (ONO) is deposited over the surface of the semiconductor substrate.