Suppose a 'n'- type wafer is created by doping Si crystal having `5xx10^(28) "atoms"//m^(3)` with 1 ppm concentration of As. On the surfabe 200 ppm Boron is added to create 'p' region in this wafer. Considering `n_(i)=1.5xx10^(16)m^(-3)`, (i) Calculate the densities of the charge carriers in the n & p regions. (ii) Comment which charge carriers would contribute largely for the reverse saturation current when diode is reverse biased.

Explanation

To solve the problem step by step, we will calculate the densities of charge carriers in both the n-type and p-type regions of the silicon wafer and then determine which charge carriers contribute to the reverse saturation current when the diode is reverse biased.

### Step 1: Calculate the density of charge carriers in the n-type region

1. **Identify the given data:**
- Concentration of Si atoms, \(N_{Si} = 5 \times 10^{28} \, \text{atoms/m}^3\)
- Concentration of As (n-type dopant) = 1 ppm = \(1 \times 10^{-6}\)
- Intrinsic carrier concentration, \(n_i = 1.5 \times 10^{16} \, \text{m}^{-3}\)
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