摘要:
An integrated fuse element is capable of being programmed to high resistance in low voltage process technology. The fuse includes a stack of an undoped polysilicon layer and a silicide layer. A voltage applied across the stack is increases until a first agglomeration event occurs, whereby a discontinuity is formed in the silicide layer. The current is further increased to cause a second agglomeration event whereby the size of the discontinuity is increased. Each agglomeration event increases the resistance of the fuse. An extended-drain MOS transistor, capable of sustaining high voltage, is connected in series with the fuse for programming the fuse. The transistor includes: a well region in a substrate, the well region forming the drain of the transistor; an insulating trench in the well; and a polysilicon gate extending over a portion of the substrate, a portion of the well and a portion of the trench, wherein upon reverse-biasing the junction between the well and the substrate a depletion region is formed which encompasses at least the entire portion of the surface region of the well over which the polysilicon extends.
摘要:
An integrated fuse element is capable of being programmed to high resistance in low voltage process technology. The fuse includes a stack of an undoped polysilicon layer and a silicide layer. A voltage applied across the stack is increases until a first agglomeration event occurs, whereby a discontinuity is formed in the silicide layer. The current is further increased to cause a second agglomeration event whereby the size of the discontinuity is increased. Each agglomeration event increases the resistance of the fuse. An extended-drain MOS transistor, capable of sustaining high voltage, is connected in series with the fuse for programming the fuse. The transistor includes: a well region in a substrate, the well region forming the drain of the transistor; an insulating trench in the well; and a polysilicon gate extending over a portion of the substrate, a portion of the well and a portion of the trench, wherein upon reverse-biasing the junction between the well and the substrate a depletion region is formed which encompasses at least the entire portion of the surface region of the well over which the polysilicon extends.
摘要:
The silicon real estate consumed by a conventional Schottky diode is reduced in the present invention by forming the Schottky diode through a field oxide isolation region. Etching through the field oxide isolation region requires extra etch time which is provided by conventional etch steps that typically specify a 50-100% overetch during contact formation.
摘要:
A sense amplifier places a low positive voltage, such as 0.1 to 0.3 volts, on a bit line instead of ground when a memory cell is read by utilizing a current source circuit to output a reference current that biases a Schottky diode. The current source circuit is implemented with a Schottky diode that utilizes the reverse-biased leakage current of the diode to form the reference current. The current source circuit can also be implemented with a current mirror circuit.
摘要:
A reference current generator outputs a reference current which is insensitive to temperature variations by utilizing two gated diodes to output currents. The currents output by the gated diodes are divided to produce the reference current which, due to the cancellation of terms, is defined by the ratio of the gate areas of the gated diodes. In addition, by utilizing two oscillators, which run at different frequencies, to drive the gated diodes, the reference current may alternately be defined by the ratio of the two frequencies.
摘要:
The potential on a pixel cell having a gated diode and a read out transistor is set to an initial level prior to an image integration period. During the image integration period, absorbed photons cause the potential on the pixel cell to change. After the image integration period, the pixel cell is then reset and read out by applying a number of pulses to the gated diode. Each of the pulses causes a fixed amount of charge to be injected into the cell. When the potential on the cell has again returned to the initial level, the number of absorbed photons is determined by counting the number of pulses that were required to return the potential to the initial level. The read out transistor is used to determine when the potential is at the initial level by biasing the transistor to output a current that corresponds to the potential on the pixel cell.
摘要:
A sense amplifier places a low positive voltage, such as 0.1 to 0.3 volts, on a bit line instead of ground when a memory cell is read by utilizing a current source circuit to output a reference current that biases a Schottky diode. The current source circuit is implemented with a Schottky diode that utilizes the reverse-biased leakage current of the diode to form the reference current. The current source circuit can also be implemented with a current mirror circuit.
摘要:
An ESD protection device for use with an integrated circuit that provides a low impedance resistive path between IC pads (including Vdd and Vss pads) when power to the IC is off, while assuring adequate isolation between the IC pads when the power is on. The device includes a semiconductor substrate (typically a p-type Si substrate) and at least two vertically integrated pinch resistors formed in the semiconductor substrate. Each of the vertically integrated pinch resistors is connected to a common electrical discharge line and to a pad. Each of the vertically integrated pinch resistors includes a deep well region and a first surface well region, both of the second conductivity type (typically n-type). The first surface well region circumscribes the deep well region, thereby forming a narrow channel region of the first conductivity type (e.g. p-type) therebetween. When no potential is applied to the first surface well regions (i.e. power is off), the two vertically integrated pinch resistors connected by the common electrical discharge line provide a low impedance resistive path between the pads for shunting ESD current. When a potential is applied to the first surface well region by the IC power supply (i.e. power is on), however, the width of the narrow channel region is pinched-off due to a potential-produced depletion region in the narrow channel region, thereby isolating the pads from each other. A process for the formation of the ESD protection device involves sequential formation of each of the device regions in a semiconductor substrate.
摘要:
An analog circuit starter current source device with automatic shut-down capability. The device includes a semiconductor substrate (typically p-type) with a deep well region (typically n-type) below its surface, a first surface well region (typically n-type) on the surface of the substrate that circumscribes the deep well region, and a narrow channel region (typically p-type) separating the deep well region from the first surface well region. The device also includes a first contact region for connecting the first surface well region to the analog circuit, and a second contact region for connecting a substrate region above the deep well to the analog circuit. The configuration provides a variable-width vertical resistor current path capable of starting an analog circuit and then being automatically shut-down by application of a potential to the first contact region sufficient to produce a depletion region that pinches-off the narrow channel region. A process for forming the starter current source device is also provided. The process includes first providing a semiconductor substrate (e.g. p-type), then forming a deep well region (e.g. n-type) below its surface. This is followed by the formation of a first surface well region (e.g. n-type) on the surface of the substrate such that the first surface well region circumscribes the deep well region, thereby producing a narrow channel (e.g. p-type) therebetween. Finally, a first contact region is formed on the surface of the first surface well region, while a second contact region is formed on the surface of semiconductor substrate above the deep well region.
摘要:
The silicon real estate consumed by a conventional Schottky diode is reduced in the present invention by forming the Schottky diode through a field oxide isolation region. Etching through the field oxide isolation region requires extra etch time which is provided by conventional etch steps that typically specify a 50-100% overetch during contact formation.