Abstract:
A method of fabricating memory cells of a mask ROM device. A plurality of source/drain regions extending along a first direction is formed by implanting impurities into a semiconductor substrate, constituting bit lines of the memory cells. A code oxide layer is formed on a designated area of the semiconductor substrate defined by a barrier layer using a liquid-phase deposition process, whereby a multi-state mask ROM is fabricated by repeatedly performing the liquid-phase deposition process to form a series of coding oxide layers having increasing thicknesses. A gate oxide layer is formed on a portion of the semiconductor substrate not covered by the coding oxide layers. The thickness of the gate oxide layer is smaller than that of the coding oxide layers. A plurality of gate electrodes extending along a second direction orthogonal to the first direction is formed by depositing and patterning a conducting layer on the coding oxide layer and the gate oxide layer, constituting word lines of said memory cells. The cross area of every two adjacent bit lines and one word line thereby forms a memory cell of the mask ROM wherein threshold voltages of the memory cells are altered proportional to the thicknesses of the gate oxide layer and the coding oxide layers.
Abstract:
An exemplary ESD protection device is adapted for a high-voltage tolerant I/O circuit and includes a stacked transistor and a gate-grounded transistor e.g., a non-lightly doped drain type gate-grounded transistor. The stacked transistor and the gate-grounded transistor are electrically coupled in parallel between an I/O pad and a grounding voltage of the high-voltage tolerant I/O circuit.
Abstract:
A method for evaluating failure rate, which is applied to a plurality of semiconductor chips with error checking and correcting function includes the following steps. A first read-write test operation is applied to the semiconductor chips, thereby obtaining a plurality of first failure bit counting values. The error checking and correcting function of each of the semiconductor chips is off. An aging test is applied to the semiconductor chips. A second read-write test operation as the first read-write test operation is applied to the semiconductor chips, thereby obtaining a plurality of second failure bit counting values. The number of the semiconductor chips, the first failure bit counting values, the second failure bit counting values and an error checking and correcting coefficient are calculated to obtain a failure rate of the semiconductor chips.
Abstract:
The ESD protection circuit is electrically connected between a first power rail and a second power rail, and includes an ESD protection device, a switching device electrically connected between the ESD protection device and a first power rail, and a low-pass filter electrically connected between the first power rail and the first switching device. The ESD protection device includes a BJT and a first resistor electrically connected between a base of the BJT and a first power rail. When no ESD event occurs, a potential of the base is larger than or equal to a potential of an emitter of the BJT. When the ESD event occurs, the potential of the base is smaller than the potential of the emitter.
Abstract:
An AC stress test circuit for HCI degradation evaluation in semiconductor devices includes a ring oscillator circuit, first and second pads, and first and second isolating switches. The ring oscillator circuit has a plurality of stages connected in series to form a loop. Each of the stages comprises a first node and a second node. The first and second isolating switches respectively connect the first and second pads to the first and second nodes of a designated stage and both are switched-off during ring oscillator stressing of the designated stage. The present invention also provides a method of evaluating AC stress induced HCI degradation, and a test structure.
Abstract:
An electrostatic discharge (ESD) device is described, including a gate line, a source region at a first side of the gate line, a comb-shaped drain region disposed at a second side of the gate line and having comb-teeth parts, a salicide layer on the source region and the drain region, and contact plugs on the salicide layer on the source region and the drain region. Each comb-teeth part has thereon, at a tip portion thereof, at least one of the contact plugs.
Abstract:
The ESD protection circuit is electrically connected between a first power rail and a second power rail, and includes an ESD protection device, a switching device electrically connected between the ESD protection device and a first power rail, and a low-pass filter electrically connected between the first power rail and the first switching device. The ESD protection device includes a BJT and a first resistor electrically connected between a base of the BJT and a first power rail. When no ESD event occurs, a potential of the base is larger than or equal to a potential of an emitter of the BJT. When the ESD event occurs, the potential of the base is smaller than the potential of the emitter.
Abstract:
A method for fabricating a test structure, in which, a heating plate is formed on the wafer for heating a structure to be tested positioned above or adjacent to the heating plate. The heating plate produces heat by electrically connecting to a current. Thus, the heat provided by the heating plate and the electric input/output into/from the structure to be tested are controlled separately and not influenced each other.
Abstract:
A method for manufacturing a semiconductor device includes providing a substrate having at least a gate structure formed thereon, forming LDDs in the substrate respectively at two side of the gate structure and a spacer at sidewalls of the gate structure, forming a source/drain in the substrate at two side of the gate structure, performing ant etching process to form recesses respectively in the source/drain, forming a barrier layer in the recesses; and performing a salicide process.
Abstract:
A method for removing a diffusion barrier layer on pad regions and diminishing the effect of plasma ions induced when removing a photoresist layer by a plasma asher. A two stage rapid thermal processing step is applied to the partially-removed diffusion barrier layer before a metal layer is formed. The first stage lasts a longer period of time at a lower temperature, for example, in the range of between 50 and 60 seconds at a temperature of about 600.degree. C. The second stage lasts a shorter period of time at a higher temperature, for example, in the range of between 20 and 30 seconds at a temperature of about 750.degree. C.