Tower Semiconductor Ltd.

Itzhak Edrei

Yakov Roizin

Efraim Aloni

Jeff Levy

Zmira Lavie

Zmira Shterenfeld-Lavie

Aviad Roth

Flash-to-ROM conversion is performed by converting single transistor flash memory cells to single transistor ROM cells. An S-Flash memory cell is converted to a programmed ROM cell by introducing a threshold voltage implant into the channel region of the S-Flash memory cell. Alternately, an S-Flash memory cell is converted to a programmed ROM cell by introducing a threshold voltage implant into a substrate region in alignment with an edge of the gate electrode of the S-Flash memory cell. The width of the mask through which this threshold voltage implant is performed can be varied, such that the threshold voltage implant region can have different dopant concentrations, thereby allowing multiple bits to be represented by the programmed ROM cell. In another embodiment, a Y-flash memory cell is converted to a programmed ROM cell by adjusting the length of a floating gate extension region of the Y-Flash memory cell.

Flash-to-ROM conversion

An embedded semiconductor memory is fabricated by: forming diffusion bit line regions in a semiconductor substrate; then thermally oxidizing the upper surface of the substrate, thereby forming a bottom oxide layer over the substrate and simultaneously forming bit line oxide regions over each of the diffusion bit line regions; and then forming an intermediate dielectric layer (e.g., silicon nitride), over the bottom oxide layer and the bit line oxide regions. CMOS well implants are then performed in a CMOS section of the device through the silicon nitride layer and bottom oxide layer. The silicon nitride layer and bottom oxide layer are then removed in the CMOS section, and a top dielectric layer, such as a high-temperature oxide or a high-k dielectric, is deposited. The top dielectric layer completes a memory stack of the memory device, and forms a gate dielectric layer of a high voltage transistor in the CMOS section.

SONOS embedded memory with CVD dielectric

A semiconductor process is provided that creates transistors having polycide gates in a first region of a semiconductor substrate and transistors having salicide gates in a second region of the semiconductor substrate. A polysilicon layer having a first portion in the first region and a second portion in the second region is formed over the semiconductor substrate. Then, a first dielectric layer is formed over the second portion of the polysilicon layer. Metal silicide is deposited over first portion of the polysilicon layer and the first dielectric layer. The metal silicide overlying the first dielectric layer is removed as is the first dielectric layer. The metal silicide and the polysilicon layer are etched to form polycide gates in the first region and polysilicon gates in the second region. A second dielectric layer is formed over the first region. Refractory metal is then deposited over the resulting structure and reacted. As a result, salicide is formed on the polysilicon gates of the second region.

Semiconductor chip having both polycide and salicide gates and methods for making same

An improved method for depositing the cap layer of a flow fill layer of an integrated circuit. The cap layer is deposited in at least two steps, instead of all at once.

Growing community of inventors

Haifa, Israel

Itzhak Edrei