Question

Which of the following is not true about diffused resistor?

(a) Limitation due to small range of resistance

(b) Resistance depends upon surface geometry

(c) Resistance depends on diffusion characteristic of material

(d) Diffused resistors are non-economical

I had been asked this question in exam.

This is a very interesting question from Active and Passive Components of IC topic in portion IC Fabrication of Linear Integrated Circuits

Answer 1

The correct answer is:

(d) Diffused resistors are non-economical

Explanation:

Diffused resistors are economical and widely used in integrated circuits because they are fabricated as part of the IC manufacturing process, utilizing existing steps like diffusion and ion implantation. Here's why the other options are true:

• (a) Diffused resistors have a limited range of resistance due to constraints in material and diffusion processes.
• (b) The resistance depends on surface geometry, specifically the $L/W$ ratio.
• (c) The resistance also depends on the diffusion characteristics of the material, such as the doping concentration and depth.

Option (d) is not true because diffused resistors are cost-effective in the context of integrated circuit fabrication.