ABSTRACT
This chapter discusses the temperature dependence of electrical parameter variations in bipolar devices. The parameters investigated for bipolar devices include intrinsic carrier concentration, thermal voltage, mobility, current gain, leakage current, collector-emitter saturation voltage, and Voltage Transfer Characteristic shift. When every available extrinsic electron has been transferred, the electron density in the conduction band is virtually constant with temperature until the concentration of intrinsic carriers becomes comparable to the extrinsic density. Semiconductor materials are generally doped such that the extrinsic range extends beyond the highest temperature at which the device is to be used. The ideal p-n junction (ideal diode equation) is affected by temperature due to variations in the saturation current, which is function of the intrinsic carrier concentration and thermal voltage. Intrinsic carrier concentration is exponentially dependent on steady-state temperature, and thermal voltage is linearly dependent on steady-state temperature.
