1. Which type of CMOS process involves the creation of both n-type and p-type wells on the same substrate?
a) Twin tub process
b) Bipolar process
c) Silicon on insulator process
d) Bulk CMOS process
Answer: a) Twin tub process
Explanation: In a twin tub process, both n-type and p-type wells are created on the same substrate, allowing for the fabrication of both NMOS and PMOS transistors.
2. What is the primary purpose of interconnects in CMOS technology?
a) To connect transistors to power supplies
b) To connect transistors within the same chip
c) To connect multiple chips together
d) To provide thermal insulation
Answer: b) To connect transistors within the same chip
Explanation: Interconnects in CMOS technology are used to connect various components (transistors, resistors, etc.) within the same integrated circuit chip.
3. Which of the following is NOT a typical element of layout design rules in CMOS technology?
a) Minimum feature size
b) Metal layer thickness
c) Spacing between adjacent features
d) Transistor threshold voltage
Answer: d) Transistor threshold voltage
Explanation: Layout design rules in CMOS technology primarily dictate parameters such as minimum feature size, spacing between features, and metal layer thickness, but they do not directly involve the transistor threshold voltage.
4. What is latch-up in CMOS technology?
a) A type of transistor
b) A type of interconnect
c) A phenomenon where the device enters a low-power mode
d) An undesirable condition where a parasitic thyristor is inadvertently triggered
Answer: d) An undesirable condition where a parasitic thyristor is inadvertently triggered
Explanation: Latch-up is a phenomenon in CMOS technology where a parasitic thyristor is triggered, causing a low-resistance path between the power supply rails and potentially damaging the device.
5. What is the physical origin of latch-up in CMOS technology?
a) Electrostatic discharge
b) Hot carrier injection
c) Parasitic bipolar transistors
d) Capacitive coupling
Answer: c) Parasitic bipolar transistors
Explanation: Latch-up occurs due to the triggering of parasitic bipolar transistors within the CMOS structure, leading to the formation of a low-resistance path between the power supply rails.
6. How can latch-up in CMOS technology be prevented?
a) By increasing the supply voltage
b) By reducing the operating temperature
c) By optimizing the layout design
d) By increasing the transistor size
Answer: c) By optimizing the layout design
Explanation: Optimizing the layout design, such as placing guard rings and isolating sensitive components, can help prevent latch-up in CMOS technology.
7. Which technique is commonly used for internal latch-up prevention in CMOS technology?
a) Doping the substrate
b) Inserting PN junctions
c) Implementing guard rings
d) Adding external resistors
Answer: c) Implementing guard rings
Explanation: Guard rings are commonly used in CMOS technology to prevent latch-up by creating a barrier around sensitive components to divert the parasitic currents.
8. In a basic n-well CMOS process, what type of well is created for PMOS transistors?
a) n-type well
b) p-type well
c) Silicon well
d) Guard well
Answer: b) p-type well
Explanation: In a basic n-well CMOS process, p-type wells are created for PMOS transistors, while n-type wells are created for NMOS transistors.
9. Which process enhancement technique involves the addition of impurities to alter the conductivity of specific regions of the substrate?
a) Ion implantation
b) Chemical vapor deposition
c) Plasma etching
d) Thermal oxidation
Answer: a) Ion implantation
Explanation: Ion implantation is a process enhancement technique in CMOS technology where impurities are added to specific regions of the substrate to alter their conductivity, enabling precise doping of semiconductor materials.
10. Which of the following is NOT a component of CMOS technology?
a) Transistor
b) Capacitor
c) Resistor
d) Diode
Answer: d) Diode
Explanation: While diodes can be integrated into CMOS circuits for various purposes, including ESD protection, they are not considered as fundamental to CMOS technology as transistors, capacitors, or resistors.