Martin Sandén

Random telegraph signal noise in SiGe heterojunction bipolar transistors

In this work, random telegraph signal (RTS) noise in SiGe heterojunction bipolar transistors (HBTs) was characterized both as a function of bias voltage and temperature. The RTS amplitudes were fo ...

A low-complexity 62-GHz fT SiGe heterojunction bipolar transistor process using differential epitaxy and in situ phosphorus-doped poly-Si emitter at very low thermal budget

A low-complexity SiGe heterojunction bipolar transistor process based on differential epitaxy and in situ phosphorus doped polysilicon emitter technology is described. Silane-based chemical vapor d ...

Decreased low frequency noise by hydrogen passivation of polysilicon emitter bipolar transistors

The effect of hydrogen passivation by forming gas annealing (FGA) on the bipolar junction transistor low frequency noise was investigated. The results demonstrated a reduced 1/f noise component by a factor of five after FGA, which resulted in a reduced corner frequency. An equivalent input noise spectral density (S-IB) dependence on base current (IB) of S-IB similar to I-B(2) and on emitter area (A(E)) of S-IB similar to A(E)(-1) was observed, both before and after FGA. The interpretations of the results were (a) the 1/f noise was due to carrier number fluctuation, (b) the noise sources were homogeneously distributed over the polysilicon/monosilicon emitter interfacial oxide, and

An analytical model for space-charge region capacitance based on practical doping profiles under any bias conditions

An analytical model is presented For quasi-static capacitance of the space-charge region in a p-n junction. The model is valid for realistic junction doping profiles under any bias conditions. It c ...

STATISTICAL SIMULATIONS OF THE LOW-FREQUENCY NOISE IN POLYSILICON EMITTER BIPOLAR TRANSISTORS USING A MODEL BASED ON GENERATION-RECOMBINATION CENTERS

In this work, a new, physically based model for the low-frequency noise is investigated by statistical simulations. The proposed model is based only on superposition of generation-recombination centers, and can predict the frequency-, current- and area-dependence of the low-frequency noise, as well as the area-dependence of the variation in the noise level. Measurements on Bipolar Junction Transistors (BJTs) are found to be in excellent agreement with the simulated results. For devices with large emitter areas AE, the model predicts a spectral density SIn ~ 1/f. For devices with submicron AE, SIn strongly deviates from a 1/f behavior, and several generation-recombination centers dominate the spectrum. However, the average spectrum , calculated from several BJTs with identical AE, has a frequency dependence ~ 1/f. The extracted areal trap density within the frequency range 1-104 Hz is nT = 3 × 109cm-2. The simulations show that the condition for observing g-r noise in the spectrum, strongly depends on the number of traps NT, as well as the distribution of the corresponding energy level for the traps. The relative noise level is found to vary in a non-symmetrical way around , especially for small AE. For AE , and above . For AE > 0.3 μm2, the variation is found to be .

Impact on Low-Frequency Noise Properties from Lateral Design of Differentially Grown SiGe HBTs

SiGe heterojunction bipolar transistors (HBTs) are suitable for wireless applications due to their high speed, low high-frequency noise and low power dissipation. For some applications, such as voltage-controlled oscillators (VCO’s), the device must also exhibit low 1/ noise which will act to suppress undesired phase noise. In this work, SiGe HBTs based on chemical vapour deposition (CVD) epitaxy have been studied. The SiGe epitaxial film was grown differentially with a monocrystalline phase on top of the silicon collector, and a polycrystalline phase on top of the LOCOS. Figure 1 shows a cross-sectional TEM picture of the HBT investigated in this work. The interface between the polycrystalline and epitaxial Si/SiGe stack ...............

Lateral base design rules for optimized low-frequency noise of differentially grown SiGe heterojunction bipolar transistors

Abstract The low-frequency noise dependence on lateral design parameters was investigated for SiGe heterojunction bipolar transistors fabricated by differential epitaxy. The low-frequency noise was found to vary substantially as a function of the extrinsic base design. The dominant noise sources were located either at the interface between the polycrystalline and epitaxial Si/SiGe base, in the epitaxial Si/SiGe base link region, in the base–emitter depletion region, or at the thin SiO 2 interface layer between the polysilicon and monosilicon emitter. Boron was found to passivate interfacial traps, acting as low-frequency noise sources. Generation–recombination noise with a strong dependence on the lateral electrical field was observed for some of the designs.

The effect of hydrogen passivation on electrical characteristics of double-polysilicon self-aligned bipolar transistors

Abstract The influence of hydrogen passivation using forming gas annealing (FGA), on the electrical performance of double-polysilicon self-aligned bipolar junction transistors was investigated. While the collector current remained essentially unaffected after FGA, the base current decreased substantially. As a result, the peak DC current gain increased by a factor of three. Identification of the various base current components showed that the SiO 2 /monosilicon interface area along the perimeter of the emitter window, were effectively passivated after FGA, both in the quasi-neutral base and in the space charge region. The FGA treatment was also found to lead to an increase in the peak cut-off frequency by up to 40%. This is explained by a decrease in emitter–base junction capacitance, which was verified experimentally.

A new test structure for direct extraction of SPICE model parameters for double polysilicon bipolar transistors

Direct extraction of ten core SPICE model parameters for double polysilicon bipolar junction transistors (BJTs) was performed using a new test structure. The test structure was basically identical to a real BJT, but without the intrinsic base. Hence, the extrinsic parasitics of the test structure were identical to the BJT. From the test structure small-signal model, all extrinsic model parameters were directly extracted from the measured scattering parameters over the frequency range of 1 to 18 GHz. The values of the extracted parameters were in good agreement compared to those obtained using other conventional methods.

A new test structure for extracting extrinsic parameters in double-polysilicon bipolar transistors

A new test structure for parameter extraction is presented and implemented in a double-polysilicon bipolar junction transistor (BJT) process. The test structure is basically a real BJT, but without the intrinsic base. The test structure allows extraction of the base, collector and emitter impedances, and the extrinsic base-collector capacitance.