A new model for the low-frequency noise and the noise level variation in polysilicon emitter BJTs
2002 (English)In: IEEE Transactions on Electron Devices, ISSN 0018-9383, Vol. 49, no 3, 514-520 p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2002. Vol. 49, no 3, 514-520 p.
bipolar transistor, interfacial oxide, low-frequency noise, noise modeling, polysilicon emitter, bipolar junction transistors, random telegraph signal, 1/f noise
IdentifiersURN: urn:nbn:se:kth:diva-21335ISI: 000173991900025OAI: oai:DiVA.org:kth-21335DiVA: diva2:340033
QC 201005252010-08-102010-08-10Bibliographically approved