Question

The uses of silicon dioxide in modern integrated circuit fabrication process :
• [A.] To serve as mask against diffusion of dopants into silicon
• [B.] To provide surface passivation
• [C.] To isolate one device from another device
• [D.] To act as a component in MOS structures
• [E.] To provide electrical isolation of multi-level metallization systems Choose the correct answer from the options given below :

• A. A, B, C, E
• B. A, B, C, D, E
• C. A, B, C, D Only
• D. A, B, C Only

Hint:

Major uses of \(SiO_2\):
• Diffusion masking
• Surface passivation
• Device isolation
• MOS gate oxide
• Interlayer insulation

Answer 1

The Correct Option is B

Concept: Silicon dioxide: \[ SiO_2 \] is one of the most important materials used in IC fabrication. Its excellent insulating and chemical properties make it extremely useful in semiconductor technology.

Step 1: Analyze statement A. Silicon dioxide acts as: \[ \text{Diffusion mask} \] during doping operations. It prevents dopants from entering protected regions. Hence: \[ A \text{ is correct} \]

Step 2: Analyze statement B. Surface passivation means:
• Protecting semiconductor surface
• Reducing contamination and surface states \(SiO_2\) performs this role efficiently. Thus: \[ B \text{ is correct} \]

Step 3: Analyze statement C. Silicon dioxide electrically isolates nearby devices on IC chip. Therefore: \[ C \text{ is correct} \]

Step 4: Analyze statement D. MOS stands for: \[ \text{Metal Oxide Semiconductor} \] The oxide layer used is: \[ SiO_2 \] Hence: \[ D \text{ is correct} \]

Step 5: Analyze statement E. In multilayer metallization:
• Metal layers must remain electrically isolated. Silicon dioxide serves as: \[ \text{Interlayer dielectric} \] Thus: \[ E \text{ is correct} \]

Step 6: Determine final answer. All statements: \[ A,\ B,\ C,\ D,\ E \] are correct.

Step 7: Write final answer. Hence the correct option is: \[ \boxed{(B)\ A,\ B,\ C,\ D,\ E} \]