What are the additional processing steps for BiCMOS fabrication?

14 Steps for BiCMOS Fabrication

• Step1: P-Substrate is taken as shown in the below figure.
• Step2: The p-substrate is covered with the oxide layer.
• Step3: A small opening is made on the oxide layer.
• Step4: N-type impurities are heavily doped through the opening.
• Step5: The P – Epitaxy layer is grown on the entire surface.

What is BiCMOS process?

BiCMOS process is essentially a combination of Bipolar transistor and CMOS transistors, it offers many technical advantages and some semiconductor foundries still provide access to BiCMOS technology.

What are the advantages and applications of BiCMOS technology?

It follows that BiCMOS technology offers the advantages of: 1) improved speed over CMOS, 2) lower power dissipation than Bipolar (which simplifies packaging and board requirements), 3) flexible I/Os (TTL, CMOS, or ECL), 4) high performance analog, and 5) latchup immunity [1.2].

What are the additional two layers in BiCMOS technology compared to other?

The npn transistors is formed in an n- well and the additional p+ base region is located in the well to form the p-base region of the transistor. The second additional layer, the buried n+subcollector (BCCD), is added to reduce the n-well (collector) resistance and thus improve the quality of the bipolar transistor.

What is difference between CMOS and BiCMOS?

BiCMOS combines the strengths of two different process technologies into a single chip: Bipolar transistors offer high speed and gain, which are critical for high-frequency analog sections, whereas CMOS technology excels for constructing simple, low-power logic gates.

What are the basic steps in manufacturing an IC?

Steps for IC fabrication

• Wafer production. The first step is wafer production.
• Masking. To protect some area of wafer when working on another area, a process called photolithography is used.
• Etching. It removes material selectively from the surface of wafer to create patterns.
• Doping.
• Metallization.

What is CMOS full form?

This phrase refers to the system configuration stored in a battery-powered memory chip known as the complementary metal-oxide semiconductor (CMOS). A computer uses these information for startup functions, including starting its basic input/output system and setting time.

What are the features of BiCMOS?

Some of the features of BiCMOS are low input impedance, low packing density, unidirectional, high output drive current etc. BiCMOS has low power dissipation. Solution: BiCMOS has high power dissipation and CMOS has low power dissipation.

What is Bimos technology?

A technology for combining bipolar transistors and metal-gate metal-oxide-semiconductor (MOS) or metal-gate complementary metal-oxide-semiconductor (CMOS) field-effect devices in a single-chip integrated circuit.

What is the difference between CMOS and BiCMOS?

What is P well process?

Polysilicon is used for formation of the gate because it can withstand the high temperature greater than 80000c when a wafer is subjected to annealing methods for formation of source and drain. Polysilicon is deposited by using Chemical Deposition Process over a thin layer of gate oxide.

Why is the fabrication process of BiCMOS so complex?

The fabrication process of this technology is comprised of both the CMOS and bipolar technologies increasing the complexity. Due to increase in the complexity of the fabrication process, the cost of fabrication also increases. As there are more devices, hence, less lithography.

Are there any advantages to using BiCMOS instead of CMOS?

Many of the advantages of CMOS fabrication, for example, do not transfer directly to BiCMOS fabrication. An inherent difficulty arises from the fact that optimizing both the BJT and MOS components of the process is impossible without adding many extra fabrication steps and consequently increasing the process cost.

How is n-well and P-well technology used in CMOS fabrication?

N- well/ P- well Technology CMOS can be obtained by integrating both NMOS and PMOS transistors over the same silicon wafer. In N–well technology an n-type well is diffused on a p-type substrate whereas in P- well it is vice- verse.

How is the twin well process used in BiCMOS?

After the buried layer alignment is finished, a twin well process is used to fabricate the N-well of the PMOS and the collector of the NPN device. Therefore, the same masks are used as for the buried layers. Again, the wafer is capped with a nitride layer which is opened at the N+ regions.