摘要:
A field oxide device (FOD) useful for electrostatic discharge (ESD) protection and other applications. The FOD is characterized as being capable of achieving a relatively low breakdown voltage and capable of handling relatively high currents during an ESD event. In general, the FOD includes a zener junction to promote an earlier breakdown of the device. The zener junction also provides a planar-like breakdown region which makes it capable of handling relatively high currents. In particular, the FOD includes a p-doped substrate having a drain-side n+ diffusion region and a source-side n+ diffusion region which are separated by a field oxide. The FOD further includes a p+ doped region that interfaces with the drain-side n+ diffusion region to form a zener junction. The breakdown voltage of the FOD can be easily set by controlling the doping concentration and energy of the p+ doped region. The FOD may additionally include one or more n+ regions at the respective boundaries of the drain-side and source-side n+ diffusion regions to provide improved junction curvature. In addition to the field oxide interposed between the drain-side and source-side n+ diffusion regions, field oxides can be added respectively at the drain and source ends to provide isolation from other devices within an integrated circuit.
摘要:
A silicon controlled rectifier (SCR) serving as an electrostatic discharge (ESD) protection device having a vertical zener junction for triggering breakdown. The SCR includes a p-doped substrate having an n-doped well, spaced-apart p+ and n+ doped regions for cathode connection formed within the n-doped well, and spaced-apart p+ and n+ doped regions for anode connection formed with the p-substrate external to the n-doped well. The SCR further includes a vertical zener junction situated between the anode n+ doped region and the n-well. The vertical zener junction has a p+ doped region sandwiched between two n+ doped regions. The n+ doped region of the vertical zener junction closest to the n-well may extend at least partially within the n-well, or be totally outside of the n-well. The SCR may further include respective field oxides between the anode p+ and n+ doped regions, between the anode n+ doped region and the vertical zener junction, and between the vertical zener junction and the n-doped well. Also provided is an n-doped substrate version of the SCR. The SCR with the vertical zener junction is characterized as having a relatively low breakdown voltage, having improved current handling capability for more reliable and robust operations, and having a breakdown voltage dependent on the doping concentration of the lighter doped p+ or n+ doped region of the vertical zener junction.
摘要:
A first embodiment of an Electrostatic Discharge (ESD) structure for an integrated circuit for protecting the integrated circuit from an ESD signal, has a substrate of a first conductivity type. The substrate has a top surface. A first region of a second conductivity type is near the top surface and receives the ESD signal. A second region of the second conductivity type is in the substrate, separated and spaced apart from the first region in a substantially vertical direction. A third region of the first conductivity type, heavier in concentration than the substrate, is immediately adjacent to and in contact with the second region, substantially beneath the second region. In a second embodiment, a well of a second conductivity type is provided in the substrate of the first conductivity type. The well has a top surface. A first region of the second conductivity type is near the top surface. A second region of the second conductivity type is in the well, substantially along the bottom of the well. A third region of the first conductivity type, is immediately adjacent to and in contact with the second region, substantially beneath the second region. A fourth region of the first conductivity type is in the well, along the top surface thereof, and spaced apart from the first region. The first region and the fourth region receive the ESD signal.
摘要:
An analog recording and playback system using non-volatile flash memory. An array of flash memory cells is used to store an analog signal and retrieve the stored analog signal on a real-time basis. A plurality of column driver circuits are coupled to the columns of flash memory cells for simultaneous programming and reading. A programming algorithm is used to write the analog signal within an operating range of the flash memory cells since the operating range may shift due to process variations. The system includes trimbit circuits to provide a trimmable initial programming voltage, programming step, programming current, read current, and select gate voltage. The system further includes a Serial Peripheral Interface ("SPI") that interfaces with a host microcontroller. The host microcontroller can send a number of commands to the system through the SPI for efficient message management. These commands include the basic commands to record or playback and various addressing and message cueing options. The system utilizes row and column redundancy to increase production yield.
摘要:
A method for fabricating a triple self-aligned non-volatile memory device is disclosed. The method includes forming isolation oxide on a substrate. A plurality of floating gates are formed by depositing and self-aligning a first polysilicon layer to the isolation oxide. A common source area is then defined on the substrate between the floating gates. A second polysilicon layer is deposited over the common source area and self-aligned with respect to the isolation oxide. A third polysilicon layer is deposited adjacent to the plurality of floating gates. A plurality of select gates are then formed by self-aligning the third polysilicon layer to the isolation oxide. Furthermore, at least one drain area is defined on the substrate.