Measurements and comparison of low frequency noise in npn and pnp polysilicon emitter bipolar junction transistors

Abstract

Monte Carlo analysis of the noise behavior in Si bipolar junction transistors and SiGe heterojunction bipolar transistors at radio frequencies

Low-frequency noise in downscaled silicon transistors: Trends, theory and practice

“…Note again that the two terms for coupled (Δn, let's say) and intrinsic (Hooge) fluctuations in equations (11) and (12) present different sides and origins for the low-frequency noise in the current transport, and they do not contradict each other. Also, the normalized noise S norm , as defined with these equations, is a power spectrum density with a unit Hz -1 , and is a convenient figure of merit, which estimates the noise "power" per a bandwidth of 1 Hz in ratio to the DC "power", that can be obtained by multiplying the nominator and denominator of the equations with the resistance of the device.…”

“…The areal dependence with increasing normalized noise in npn BJTs with smaller emitter area A E is shown in Figure 2, using the SPICE parameter K F defined from The data for more than 150 devices are collected from [10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27], and shown in Figure 2 with some points omitted for clarity. Since the numbers spread over several decades, we use geometric averaging technique [28] to extract the trend in the data from the product A E ×K F ; and the trend is A E ×K F ≈5.6×10 -9 µm 2 with logarithmic standard deviation of σ dB =3.4dB.…”

“…Therefore, the values for the low-frequency noise depend strongly on the impedance Z B of the biasing circuit in the base terminal of the BJT, even if the base DC current is unchanged. This is illustrated in Figure 3 from [12]. Consider the noise equivalent circuit for the noise measurement in Figure 3a.…”

“…Typical types of cross-over in the noise in BJT are between areal and peripheral noise sources in the emitter region [14,21,35,36,42,60], noise from tunneling through IFO and series resistances (carrier number fluctuation, or coupled noise to the injection process, precisely) and diffusion noise (mobility fluctuation, or intrinsic noise of the current flow in emitter and base regions) [10,19,21,32,42,61,62], surface and bulk noise sources [14,21,24,36,37,42,60], and for very small-area BJTs (A E ≤0.1µm 2 ), the extension length of the base to the contact via becomes an issue for the low-frequency noise [36,37], since that extension is with large area compared to A E , and it is vulnerable to the surface noise from the oxide on the top of the structure. Also, in small-area BJTs, the crossover between generation-recombination (GR), random telegraph signal (RTS) and 1/f noise becomes apparent [11,12,17,18,30,35,63]. The identification of noise sources uses many techniques, such as noise partitioning (or decomposition the total noise in several components), superposition of noise components, evolution of noise components and correlation between them with bias, area and perimeter of the emitter, fitting to physical models and equivalent circuits.…”

Overview of Power Electronic Switches: A Summary of the Past, State-of-the-Art and Illumination of the Future

“…With new technology, the size of transistors is reduced which gives high current and high-frequency gain but also increase low-frequency noise [106]. In a study by [107], it was observed that, in NPN transistors, shot noise of the base current contributes to total noise, while in a PNP transistor, generation-recombination noise adds to the total noise. Because of high mobility of electrons, NPN transistors have high conductivity and thus, switching time in NPN transistors is faster than that of in PNP transistors.…”