Abstract:
A process for fabricating non-volatile memory cells on a semiconductor substrate comprises the following steps:
forming a stack structure comprised of a first polysilicon layer (3) isolated from the substrate by an oxide layer (2); cascade etching the first polysilicon layer (3), oxide layer (2), and semiconductor substrate (1) to define a first portion of a floating gate region of the cell and at least one trench (6) bordering an active area (AA) of the memory cell; filling the at least one trench (6) with an isolation layer (7); depositing a second polysilicon layer (8) onto the whole exposed surface of the semiconductor; and etching away the second polysilicon layer (8) to expose the floating gate region formed in the first polysilicon layer (3), thereby forming extensions (9) adjacent to the above portion of the first polysilicon layer (3).
Abstract:
A process for manufacturing phase change memory cells includes the step of forming a heater element (25a) in a semiconductor wafer (10) and a storage region (31a) of a phase change material on and in contact with the heater element (25a). In order to form the heater element (25a) and the phase change storage region (31a) a heater structure is first formed and a phase change layer (31) is deposited on and in contact with the heater structure. Then, the phase change layer (31) and the heater structure are defined by subsequent self-aligned etch steps.
Abstract:
Described herein is a fuse device (1) having a fuse element (2) provided with a first terminal (10) and a second terminal (16) and an electrically breakable region (15a), which is arranged between the first terminal (10) and the second terminal (16) and is configured to undergo breaking as a result of the supply of a programming electrical quantity, thus electrically separating the first terminal (10) from the second terminal (16). The electrically breakable region (15a) is of a phase-change material, in particular a calcogenic material, for example GST.
Abstract:
Phase-change memory device, wherein memory cells (2) are arranged in rows (7) and columns (6) and form a memory array. The memory cells (2) are formed by a selection device (4) of an MOS type and by a phase-change region (3) connected to the selection device. The selection device (4) is formed by a first conductive region (32) and a second conductive region (33), which extend in a substrate (31) of semiconductor material and are spaced from one another via a channel region (34), and by an isolated control region (36) connected to a respective row (7) and overlying the channel region (34). The first conductive region (32) is connected to a connection line (42) extending parallel to the rows, the second conductive region (33) is connected to the phase-change region (46), and the phase-change region is connected to a respective column (6). The first connection line (42) is a metal interconnection line and is connected to the first conductive region (32) via a source-contact region (40) made as point contact and distinct from the first connection line (42).
Abstract:
A process for the fabrication of integrated resistive elements with protection from silicidation envisages the steps of: delimiting, in a semiconductor wafer (10), at least one active area (15); and forming, in the active area (15) at least one resistive region (21) having a pre-determined resistivity. Prior to forming the resistive region (21), on top of the active area (15) a delimitation structure (20) for delimiting the resistive region (21) is obtained, and, subsequently, protective elements (25), which extend within the delimitation structure (20) and coat the resistive region (21), are obtained.
Abstract:
The memory cell (1) is formed in a body (3) of a P-type semiconductor material forming a channel region (25) and housing N-type drain and source regions (15, 12) at two opposite sides of the channel region (25). A floating gate region (5) extends above the channel region (25). A P-type charge injection region (18) extends in the body (3) contiguously to the drain region (15), at least in part between the channel region (25) and the drain region (15). An N-type base region (21) extends between the drain region (15), the charge injection region (18), and the channel region (25). The charge injection region (18) and the drain region (15) are biased by special contact regions (19, 16) so as to forward bias the PN junction formed by the charge injection region (18) and the base region (21). The holes thus generated in the charge injection region (18) are directly injected through the base region (21) into the body (3), where they generate, by impact, electrons that are injected towards the floating gate region (5).
Abstract:
A method of making a non-volatile MOS semiconductor memory device includes a formation phase, in a semiconductor material substrate (50), of STI isolation regions (shallow trench isolation) (57) filled by field oxide (65) and of memory cells (500) separated each other by said STI isolation regions (57). The memory cells (500) include a gate electrode (52) electrically isolated from said semiconductor material substrate (50) by a first dielectric layer (53), and the gate electrode includes a floating gate (54) self-aligned to the STI isolation regions (57). The method includes a formation phase of said floating gate (54) exhibiting a substantially saddle shape including a concavity; the formation phase of said floating gate (54) includes a deposition phase of a first conformal conductor material layer (54A).