Abstract: Apparatus and associated methods relate to controlling an electric field profile within a drift region of an LDMOS device using first and second RESURF regions. The first RESURF region extends from a source end toward a drain end of the LDMOS device. The first RESURF region is adjacent to a forms a metallurgical junction with the drift region. The second RESURF layer extends from the drain end toward the source end of the LDMOS device. The second RESURF layer has an end that is longitudinally between the body contact and the source end of the first RESURF layer. A distance between the end of the second RESURF layer and the body contact is greater than a vertical distance between the end of the second RESURF layer and the body contact. A maximum electric field between the second RESURF layer and the body contact can be advantageously reduced with this geometry.

Abstract: Apparatus and associated methods relate to controlling an electric field profile within a drift region of an LDMOS device using first and second RESURF regions. The first RESURF region extends from a source end toward a drain end of the LDMOS device. The first RESURF region is adjacent to a forms a metallurgical junction with the drift region. The second RESURF layer extends from the drain end toward the source end of the LDMOS device. The second RESURF layer has an end that is longitudinally between the body contact and the source end of the first RESURF layer. A distance between the end of the second RESURF layer and the body contact is greater than a vertical distance between the end of the second RESURF layer and the body contact. A maximum electric field between the second RESURF layer and the body contact can be advantageously reduced with this geometry.

Abstract: A method of controlling an etch-pattern density of a polysilicon layer includes depositing polysilicon on a wafer. The method includes determining polysilicon-etch regions that include DMOS source regions within circuit-device areas of the wafer. The method includes calculating an etch area of the polysilicon-etch regions and then comparing the calculated etch area of the polysilicon-etch regions to a predetermined minimum etch area. If the calculated etch area is less than a predetermined threshold, the method adds polysilicon-etch regions within non-circuit-device areas to the determined polysilicon-etch regions within the circuit-device areas until the comparing step results in the calculated etch area of the polysilicon-etch regions being greater than the predetermined minimum etch area. The method includes etching the polysilicon from the polysilicon-etch regions in both the circuit-device areas and the non-circuit-device areas.

Abstract: A method of controlling an etch-pattern density of a polysilicon layer includes depositing polysilicon on a wafer. The method includes determining polysilicon-etch regions that include DMOS source regions within circuit-device areas of the wafer. The method includes calculating an etch area of the polysilicon-etch regions and then comparing the calculated etch area of the polysilicon-etch regions to a predetermined minimum etch area. If the calculated etch area is less than a predetermined threshold, the method adds polysilicon-etch regions within non-circuit-device areas to the determined polysilicon-etch regions within the circuit-device areas until the comparing step results in the calculated etch area of the polysilicon-etch regions being greater than the predetermined minimum etch area. The method includes etching the polysilicon from the polysilicon-etch regions in both the circuit-device areas and the non-circuit-device areas.

Abstract: The present invention concerns a method for contact metallization on a semiconductor where a contact hole is formed in an interlevel dielectric layer down to a doped silicon region on the silicon substrate, and then the wafer is placed into a sputtering chamber where titanium is sputtered onto the wafer. A titanium nitride layer is sputtered on top of the titanium layer in the contact hole. This invention saves time and money, because the titanium nitride layer depositing and titanium layer forming steps can occur in the same chamber without forming the boro-phosphorous silicate glass layer in between. The titanium layer reacts with the silicon to form a silicide layer at the time of the sputtering in a hot deposition or in later steps that supply heat to the wafer for a period of time. Optionally, an additional titanium layer can be formed on top of the titanium nitride layer to clean off the titanium target used to sputter the titanium and titanium nitride layers on the wafer.

Abstract: The present invention concerns a method for contact metallization on a semiconductor where a contact hole is formed in an interlevel dielectric layer down to a doped silicon region on the silicon substrate, and then the wafer is placed into a sputtering chamber where titanium is sputtered onto the wafer. A titanium nitride layer is sputtered on top of the titanium layer in the contact hole. This invention saves time and money, because the titanium nitride layer depositing and titanium layer forming steps can occur in the same chamber without forming the boro-phosphorous silicate glass layer in between. The titanium layer reacts with the silicon to form a silicide layer at the time of the sputtering in a hot deposition or in later steps that supply heat to the wafer for a period of time. Optionally, an additional titanium layer can be formed on top of the titanium nitride layer to clean off the titanium target used to sputter the titanium and titanium nitride layers on the wafer.

Abstract: A floating gate device has a control gate and a floating gate. The floating gate is for charging to set a logic state therein. Moisture is a problem in causing the floating gate to either lose its charge or becoming charged to the wrong state. A thin nitride layer deposited over the control gate and along the sides of the floating gate and control gate as a moisture barrier. This nitride layer is sufficiently thin so as to provide only insignificant attenuation of ultra-violet light used to neutralize the charge state of the floating gate. This nitride layer is not used as a passivation layer so that the desirable phoshosilicate glass (PSG) can be used for passivation.