Abstract: An improved method for fabricating a NAND-type memory cell structure. The present invention forgoes providing a contact mask implantation process prior to deposition of a metal barrier layer, which is a typical order of processing the NAND-type memory cell. Instead, in the present invention, the metal barrier layer is deposited on a core area of the NAND-type memory cell prior to contact mask implantation. Thereafter, the contact mask implantation process is performed on the structure in a conventional manner.

Abstract: A method of forming floating gate to improve tunnel oxide reliability for flash memory devices. A substrate having a source, drain, and channel regions is provided. A tunnel oxide layer is formed over the substrate. A floating gate is formed over the tunnel oxide and the channel region, the floating gate being multi-layered and having a second layer sandwiched between a first layer and a third layer. The first layer of the floating gate overlying the tunnel oxide layer includes an undoped or lightly doped material. The second layer is highly-doped. The third layer is in direct contact with a dielectric layer, e.g., an oxide-nitride-oxide stack, and is made of an undoped or lightly doped material. A dielectric material is formed over the floating gate and a control gate is formed over the dielectric material.

Abstract: A process for forming high density isolation for very large scale integration on semiconductor chips, comprising the steps of: orientation-dependent etching a portion of a semiconductor substrate to form protruding features on a surface of the semiconductor substrate; forming a layer of insulation above the etched portion of the semiconductor substrate; implanting atoms and/or ions of a non-conductive material to a first predetermined depth into the insulation layer and a second predetermined depth into the protruding features in the semiconductor substrate to provide a detectible change in material characteristic at that depth; and polishing the insulation layer and protruding features down to a depth determined by detecting the change in material characteristic to thereby remove a top portion of the protruding features to form a first surface on each of a plurality of the protruding features.

Abstract: A P-type dopant is implanted into a substrate region 94 under a select drain gate transistor field oxide region 75 at a large tilt angle .alpha., to prevent field turn-on under the select drain gate transistor field oxide region 75 in a non-volatile memory device such as a NAND flash memory device. A substrate region 114 under a select source gate transistor field oxide region 77 can also be implanted with a P-type dopant to prevent field turn-on under the region 77 if select source gates 90 and 92 are to be supplied with a voltage in operation rather than grounded. The substrate regions 94 and 114 under both the select drain gate transistor field oxide region 75 and the select source gate transistor field oxide region 77 can be implanted with the P-type dopant using a fixed-angle ion beam 120, by rotating the wafer 124 between the step of implanting one of the substrate regions and the step of implanting the other region.

Abstract: This invention describes methods for producing gate oxide regions in periphery regions of semiconductor chips, wherein the gate oxide regions have improved electrical properties. The methods involve the deposition of a barrier layer over the periphery of the semiconductor chip to prevent the introduction of contaminating nitrogen atoms into the periphery during a nitridation step in the core region of the semiconductor chip. By preventing the contamination of the gate areas of the periphery, the gate oxide regions so produced have increased breakdown voltages and increased reliability. This invention describes methods for etching the barrier layers used to protect the periphery from tunnel oxide nitridation. Semiconductor devices made with the methods of this invention have longer expected lifetimes and can be manufactured with higher device density.

Abstract: A method for fabricating a memory device is provided. A first polysilicon (poly I) layer is formed over a substrate. Poly I isolation rows are etched into the poly I layer so as to form electrically isolated poly I lines. An oxide-nitride-oxide (ONO) layer is formed over the poly I lines and field oxide portions exposed via the poly I isolation rows. A second polysilicon (poly II) layer is formed over the ONO layer. Poly II isolation rows are etched into the poly II layer so as to form electrically isolated poly II lines, the poly II isolation rows being perpendicular in direction to the poly I isolation rows, the poly II isolation rows exposing portions of the ONO layer. Heavy ions are implanted into portions of the poly I layer via the exposed portions of the ONO layer, wherein the heavy ions disrupt silicon bonds of the poly I layer portions. The exposed portions of the ONO layer and the poly I layer portions are substantially etched away.

Abstract: A NAND type flash Electrically Erasable Programmable Read-Only Memory (Flash EEPROM) includes an array of memory cells which each include a floating gate for storing charge when the cell is programmed. Select lines are used to control programming, reading and erasing of the cells. The floating gates and the select line are integrally formed from a first polysilicon layer (POLY 1). A contact area of the select line which is used to make external connection through a vertical interconnect (via) is made thicker than the floating gates to avoid punchthrough of the contact area during a dry etching step which is used to form the via. The POLY 1 layer is first formed to an initial thickness, and a silicon nitride mask layer is formed over the POLY 1 layer. The portion of the silicon nitride layer over the contact area is protected with photoresist, and the remaining area of the silicon nitride layer is etched away.

Abstract: A method of fabricating an interpolysilicon dielectric structure in a non-volatile memory includes the steps of forming a high dielectric constant layer 12 on a floating gate 10 and an oxynitride layer 14 on the high dielectric constant layer 12. A control gate 18 may be formed on the oxynitride layer 14 to produce a dual gate structure with a high capacitance and therefore a high coupling ratio.

Abstract: A method of fabricating an interpolysilicon dielectric structure in a non-volatile memory includes the steps of forming a nitride layer 12 on a floating gate 10 and a high dielectric constant layer 14 on the nitride layer 12. A control gate 18 may be formed directly on the high dielectric constant layer 14, or on a thin layer 16 of an oxide or an oxynitride on the high dielectric constant layer 14.

Abstract: A semiconductor isolation structure comprising: a semiconductor substrate with a plurality of trenches formed therein with substantially vertical sidewalls, the plurality of trenches defining at least one mesa of semiconductor material; wherein only top corners of the mesa have been converted to an oxide containing a heavy ion implant; and an insulator material filling the plurality of trenches.

Abstract: A method for fabricating a semiconductor device including a silicon substrate and plural silicon stacks thereon includes forming a nitride shield layer on the substrate and stacks to cover the stacks, such that the stacks are protected from loss of critical dimension during subsequent isolation trench formation and oxidation. In other words, the edge of each stack, and thus the critical dimension of the silicon layers of the stack, is protected from oxidation by the nitride shield layer.