In a silicon oxidation model, B/A is the linear rate constant and τ accounts for the shift in the time coordinate to account for the presence of the initial oxide layer, then the linear law is represented as:

6) In a silicon oxidation model,

B/A

is the linear rate constant and τ accounts for the shift in the time coordinate to account for the presence of the initial oxide layer, then the linear law is represented as:

1.

B/A*

(t - τ) 

2.

A/B*

(t - τ) 

3.

B/A*

(t + τ) 

4.

Bt/Aτ

Answer: C

Solution

Logical Breakdown of Silicon Oxidation

To understand the formula, we look at the Deal-Grove Model. This model describes how an oxide layer (SiO₂) grows on a silicon wafer over time.

Step 1: Understanding the Variables

• t (Time): The actual duration the silicon stays in the oxidation furnace.
• τ (Tau): This accounts for the Initial Oxide Layer. Wafers usually have a tiny bit of oxide (native oxide) before we start. τ represents the "equivalent time" it would have taken to grow that pre-existing layer.
• B/A (Linear Rate Constant): This constant tells us how fast the silicon is reacting when the oxide is very thin.

Step 2: The General Equation

The full Deal-Grove equation for oxide thickness (x_o) is:

x_o² + Ax_o = B(t ± τ)

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