# Concentration in Silicon BJT Transistor

## What is the doping concentration in the base of a silicon BJT transistor with specific parameters?

Can we calculate the doping concentration based on given data?

## Calculation of Doping Concentration in Silicon BJT Transistor

Based on the given parameters, we can determine the doping concentration in the base of the silicon BJT transistor by following a specific set of calculations.

A silicon BJT with DB=10 cm²/s, DE=40 cm²/s, WE=100 nm, WB=50 nm and Ne=10¹8 cm³ has a = 0.97. To estimate the doping concentration in the base of this transistor, we need to consider various factors such as the diffusion coefficients, emitter and base widths, and electron concentration.

Given the current gain (β) formula of β = α / (1 − α), we can calculate the collector current (Ic) and base current (Ib) of the transistor by assuming a saturation current density of Jn = 10^4 A/cm².

Subsequently, the base doping concentration (nb) can be found by utilizing the equation nb = Ib/(qAeDNb), where Ae is the emitter area and DNb is the electron diffusion coefficient in the base region. By substituting the values, we arrive at a doping concentration of 1.0 × 10¹8 cm^-3 in the base of the silicon BJT transistor.