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- Sanden, M., et al.
(författare)
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A new model for the low-frequency noise and the noise level variation in polysilicon emitter BJTs
- 2002
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Ingår i: IEEE Transactions on Electron Devices. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9383 .- 1557-9646. ; 49:3, s. 514-520
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Tidskriftsartikel (refereegranskat)abstract
- This work presents a new, physically-based model for the low-frequency noise in high-speed polysilicon emitter bipolar junction transistors (BJTs). Evidence of the low-frequency noise originating mainly from a superposition of generation-recombination (g-r) centers is presented. Measurements of the equivalent input noise spectral density (S-IB) showed that for BJTs with large emitter areas (A(E)) S-IB, is proportional to 1/f, as expected. In contrast, the noise spectrum for BJTs with submicron AE showed a strong variation from a 1/f-dependence, due to the presence of several g-r centers. However, the average spectrum (SIB) has a frequency dependence proportional to 1/f for BJTs with large as well as small AE. The proposed model, based only on superposition of g-r centers, can predict the frequency-, current-, area-, and variation-dependency of (S,,) with excellent agreement to the measurement results. The SPICE parameter K-F, extracted from (S,,) is found to be proportional to 1/A(E) with the product KF x AE = 4.3 x 10 (-17) cm(2). The relative variation in the noise level is found to be proportional to A(E)(-0.5), resulting in an absolute variation proportional to A (-1.5)(E). The g-r centers are most likely located next to the thin SiO2, interfacial layer between the polysilicon and monosilicon emitter. The areal trap density, responsible for the low-frequency noise within 1-10(4) Hz, is estimated to be n(T) = 3 X 10(9) cm(-2). From temperature measurement of one clearly observed g-r center, the extracted trap energy level and capture cross-section are 0.31 eV and 2 X 10(-19) cm(2), respectively.
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| 3. |
- Sanden, M., et al.
(författare)
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Modeling the variation of the low-frequency noise in polysilicon emitter bipolar junction transistors
- 2001
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Ingår i: IEEE Electron Device Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 0741-3106 .- 1558-0563. ; 22:5, s. 242-244
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Tidskriftsartikel (refereegranskat)abstract
- The variation of the low-frequency noise in polysilicon emitter bipolar junction transistors (BJTs) was investigated as a function of emitter area (A(E)) For individual BJTs with submicron-sized As, the low-frequency noise strongly deviated from a 1/f-dependence. The averaged noise varied as 1/f, with a magnitude proportional to A(E)(-1), while the variation in the noise level was found to vary as A(E)(-1.5). A new expression that takes into account this deviation is proposed for SPICE modeling of the the low-frequency noise, The traps responsible for the noise were located to the thin SiO2 interface between the polysilicon and monosilicon emitter, The trap's energy level, areal concentration and capture cross-section were estimated to 0.31 eV, 6 x 10(8) cm(-2) and 2 x 10(-19) cm(2), respectively.
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| 4. |
- Sanden, M., et al.
(författare)
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Statistical simulations of the low-frequency noise in polysilicon emitter bipolar transistors using a model based on generation-recombination centers
- 2001
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Ingår i: Fluctuation and Noise Letters. - 0219-4775 .- 1793-6780. ; 1:2, s. L51-L60
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Tidskriftsartikel (refereegranskat)abstract
- 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 A(E), the model predicts a spectral density S-Ia similar to 1/f. For devices with submicron A(E), S-In strongly deviates from a 1/f behavior, and several generation-recombination centers dominate the spectrum. However, the average spectrum < S-IB >, calculated from several BJTs with identical A(E), has a frequency dependence similar to 1/f. The extracted areal trap density within the frequency range 1 - 10(4) Hz is n(T) = 3 x 10(9) cm(-2). The simulations show that the condition for observing g-r noise in the spectrum, strongly depends on the number of traps N-T, 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 < S-IB >, especially for small A(E). For A(E) < 0.1 mu m(2), the model predicts a relative variation in the noise level similar to A(E)(-2) below < S-IB >, and similar to A(E)(-0.5) above < S-IB >. For A(E) > 0.3 mu m(2), the variation is found to be similar to A(E)(-0.5).
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