摘要:
High-voltage-tolerant ESD protection devices (ESDPD) for deep-submicron CMOS process were activated between LDD implanting and forming sidewall spacers. ESD-Implant (ESDI) regions are located at the ESDPD, without covering the center region under the drain contact (DC). The ESDI LDD concentration and doping profile are deep to contain drain diffusion. Regions with the ESDI have a high junction breakdown voltage (JBV) and a low junction capacitance. After forming gate sidewall spacers, high doping concentration ions implanted into active D/S regions formed a shallower doping profile of the D/S diffusion. The drain has a JBV as without this ESDI, so the ESD current (ESDC) is discharged through the center junction region under the DC to bulk, far from the ESDPD surface channel region. The ESDPD sustains a high ESD level. In an original drain JBV of an MOS this ESDI method is unchanged, i.e. the same as that having no such ESDI, so it can be used in I/O circuits with high-voltage signals in the deep-submicron CMOS. The ESD level of the IO ESDPD improves. The ESD discharge current path in the MOS device structure improves the ESD level in the output buffer MOS. ESDI regions are located at the output MOS devices, without covering the region under the DC. Regions under the DC without this ESDI have an unchanged JBV, so the ESDC discharges through the junction region under the DC to bulk. The original drain JBV of the output MOS with this ESDI method is unchanged, which is still the same as that having no such ESDI, to be used in the I/O circuits with high-voltage (5V) input signals in the deep-submicron CMOS with 3.3V or 2.5V VDD. This applies to diodes, FOD and lateral BJT devices.
摘要:
An implanting method forms high-voltage-tolerant ESD protection devices (ESDPD) for deep-submicron CMOS process activated between LDD implanting and forming sidewall spacers. ESD-Implant (ESDI) regions are located at the ESDPD, without covering the center region under the drain contact (DC). The ESDI LDD concentration and doping profile are deep to contain drain diffusion. Regions with the ESDI have a high junction breakdown voltage (JBV) and a low junction capacitance. After forming gate sidewall spacers, implant high doping concentration ions into active D/S regions forming a shallower doping profile of the D/S diffusion. The drain has a JBV as without this ESDI, so the ESD current (ESDC) is discharged through the center junction region under the DC to bulk, far from the ESDPD surface channel region. The ESDPD sustains a high ESD level. The original drain JBV of an MOS with this ESDI method is unchanged, i.e. the same as that having no such ESDI, so it can be used in I/O circuits with high-voltage signals in the deep-submicron CMOS. The ESD level of the I/O ESDPD improves. This method applies to high-voltage-tolerant I/O pins in a deep-submicron CMOS. The ESD discharge current path in the MOS device structure improves the ESD level in the output buffer MOS. ESDI regions are located at the output MOS devices, without covering the region under the DC. The method has a LDD concentration, so regions with this ESDI have a higher JBV and a lower junction capacitance. Regions under the DC without this ESDI have an unchanged JBV, so the ESDC discharges through the junction region under the DC to bulk.
摘要:
A process for forming an implanted ESD region, and for forming metal silicide blocking regions, using the same photolithographic mask for definition of these regions, has been developed. The process features the formation of an implanted ESD region, defined by a photoresist shape which in turn had been formed via exposure of a negative photoresist layer, using a specific photolithographic mask. Metal silicide regions are subsequently formed on regions of a semiconductor substrate, exposed in openings in an insulator layer, with the openings in the insulator layer defined via a photoresist shape, which in turn had been formed via exposure of a positive photoresist layer, using the same photolithographic mask previously used for definition of the implanted ESD region. In this invention we use only one photolithographic mask in the CMOS process to fabricate an ESD device having ESD implanted and metal silicide blocking regions, which can sustain higher ESD stress.
摘要:
In this invention, a novel substrate-triggered technique is proposed to effectively improve the electrostatic discharge (ESD) robustness of integrated circuit (IC) products. The ESD protection circuit derived from the substrate-triggered technique is comprised of a metal-oxide-semiconductor (MOS) transistor and an ESD detection circuit. The MOS transistor is composed of a bulk region, a gate, a source region coupled to a power rail, and a drain region couple to a pad. The source region, the bulk region and the drain region further construct a parasitic bipolar junction transistor (BJT) The ESD detection circuit is located between, and connected to, the power rail and the pad. During normal operation, the ESD detection circuit maintains the coupling of the bulk region to the first power rail. During an ESD event, the ESD detection circuit biases the bulk region to trigger the BJT thereby releasing ESD stress. Research and experiment demonstrate the substrate-triggered technique can substantially improve the ESD protection level of an MOS transistor.
摘要:
An ESD protection component with a deep-N-well structure in CMOS technology and the relevant circuit designs are proposed in this invention. The ESD protection component comprises a lateral silicon controlled rectifier (SCR) and a deep N-well. The SCR comprises a P-type layer, an N-type layer, a first N-well and a first P-well. The P-type layer is used as an anode of the SCR; the N-type layer is used as a cathode of the SCR; the first N-well is located between the P-type layer and the N-type layer and is contacted with the P-type layer; and the first P-well is contacted to the first N-well and the N-type layer. The deep N-well is located between the first P-well and the P-substrate, and is used to isolate the electric connection between the P-substrate and the first P-well. A plurality of these ESD protection components arbitrarily connected in series increases the total holding voltage of ESD protection circuit, thus preventing occurrences of latch-up.
摘要:
Novel PMOS-bound and NMOS-bound diodes for ESD protection, together with their application circuits, are disclosed in this invention. The PMOS-bound (or NMOS bound) diode has a PMOS (or an NMOS) structure. The source/drain region enclosed by the control gate of the PMOS (or NMOS) is used as an anode (or cathode) of the PMOS-bound (or NMOS-bound) diode. The base of the PMOS (or NMOS) is used as a cathode (or anode) of the PMOS-bound (or NMOS-bound) diode. The control gate prevents any shallow trench isolation region from forming beside the p-n junction of the PMOS-bound (or NMOS-bound) diode, such that the ESD sustaining level doesn't suffer from the formation of the STI regions. Furthermore, by ensuring proper bias to the control gate during an ESD event, the turn-on speed of the PMOS-bound or NMOS-bound diode can be increased, such that the overall ESD level of an IC chip is improved. By applying the PMOS-bound or NMOS-bound diode, ESD protection circuits for I/O buffer, power-rail ESD clamping circuits and whole-chip ESD protection systems are also provided.
摘要:
An apparatus of preventing integrated circuits from interfering by electrostatic-discharge (ESD), applied in an internal circuit and an input pad, both coupled with a first power line and a second power line, comprises a voltage clamp circuit and a voltage bias circuit. The voltage clamp circuit, with a transistor, connects to the second power line for clamping potential level through the voltage clamp circuit. The voltage bias circuit, with at least one diode coupled in series, connects to the voltage clamp circuit and the first power line for biasing the voltage clamp circuit to the second power line.
摘要:
A diode string with very low leakage current is used in power supply ESD clamp circuits. By adding an CMOS-Controlled Lateral SCR device into the cascaded diode string, the leakage current of this new diode string with 6 cascaded diodes under 5 Volts (3.3 Volts) forward bias can be controlled below 2.1 (1.07) nA at a temperature of 125° C. in a 0.35 &mgr;m silicide CMOS process. The holding voltage of this design with the CMOS-Controlled Lateral SCR can be linearly adjusted by changing the number of the cascaded diodes in the diode string for the application among the power lines with different voltage levels. The ESD level of this ESD clamp circuit is greater than 8,000 Volts in the Human-Body-Model ESD test. The diodes string is suitable for portable or low-power CMOS Integrated Circuit (IC) devices.
摘要:
An MOS-controlled, lateral SCR device including a semiconductor substrate of a first doping type; a first well region formed in the substrate and being of a second doping type which is different from the first doping type; a second well region formed in the substrate, being of the second doping type, and being spaced apart from the first well region so as to define an intermediate region separating the first and second well regions from each other; a first region formed within the first well region and extending into the intermediate region between the first and second well regions, the first region being of the second doping type; a second region formed within the second well region and extending into the intermediate region between the first and second well regions, the second region being of the second doping type; and a control gate bridging over the intermediate region between the first and second regions.
摘要:
In this invention, a whole-chip ESD protection scheme with the SCR string or the SCR/diode-mixed string are proposed to protect the mixed-voltage CMOS IC's against the ESD damage. The SCR string or the SCR/diode-mixed string is placed between the separated power lines. The ESD current is arranged to be discharged through the SCR string or the SCR/diode-mixed string and the ESD clamps between the power lines. Therefore, the internal circuits and the interface circuits between the circuits with different power supplies can be prevented from ESD damages. The number of the SCR's or the diodes in the SCR string or the SCR/diode-mixed string connected between the different power lines is dependent on the voltage difference between the different power supplies in the mixed-voltage CMOS IC's. When the IC is in the normal operating conditions, such SCR string or the SCR/diode-mixed string between the different power lines is kept off to maintain the independence of the power supplies in the mixed-voltage COMS IC.