Extraction of emitter and base series resistances of bipolar transistors from a single DC measurement

Abstract

A new procedure for extracting the emitter and base series resistances of bipolar junction transistors is presented. The parameters are extracted from a single measurement in the forward active region on one transistor test structure with two separate base contacts, making it a simple and attractive tool for bipolar transistor characterization. The procedure comprises two methods for extracting the emitter resistance and two for extracting the base resistance. The choice of method is governed by the amount of current crowding or conductivity modulation present in the intrinsic base region. The new extraction procedure was successfully applied to transistors fabricated in an in-house double polysilicon bipolar transistor process and a commercial 0.8-m single polysilicon BiCMOS process. We found that the simulated and measured Gummel characteristics are in excellent agreement and the extracted series resistances agree well with those obtained by means of HF measurements.By adding external resistors to the emitter and base and then extracting the series resistances, we verified that the two base contact test structure offers a simple means of separating the influence of emitter and base series resistances on the transistor characteristics.

Scalable Approach for HBT's Base Resistance Calculation

“…Concerning the extrinsic base resistance extraction procedure, the standard method described in [3] and [7] using lines intersect is found to be rather inaccurate and noisy [5], [6]. This paper proposes a new method based on a linear regression which improves the result reliability and demonstrates the external base resistance bias independence.…”

“…It is the only valid solution in literature to electrically disconnect the two base terminals as it has been pointed out in [4]. Unfortunately, in [5], [6] and [7] the emitter ring is not used, therefore the two base terminals are probably shorted by a silicided layer surrounding the emitter (low resistivity typically 10 are thus quite doubtful especially for the extrinsic contribution. Consequently, Ingvarson [5] claims that the external base resistance determination is "unreliable."…”

Experimental DC Extraction of the Base Resistance of Bipolar Transistors: Application to SiGe:C HBTs

“…Acceptable accuracy for the DUTs, which share a high CE β F , can also be reached with a simplified variant of the approach that makes use of I E (instead of I C ) on the LHS of (7) and M = 1 on the RHS, thereby avoiding the extraction of the M factor parameters (which, on the other hand, is not onerous): only small (around 5%) R B overestimations were found since I C /M is replaced by the slightly higher I E in (11). However, this procedure leads to larger errors if applied to bipolar transistor with lower β F .…”

“…The R B -V CB curve computed by setting M = 1 in (7), and thus in(11),(12), is not expected to coincide with the one evaluated by taking into account II for V CB < V CBZ ; in this case M(V CBZ ) in the V BEjZ expression (12) is indeed equal to 1.00132.…”

Investigation of the mechanism of transport across the poly/monocrystalline silicon interface in polysilicon-emitter bipolar transistors based on variations in the interface treatment process

“…One of the main challenges in experimental verification of a proposed mechanism for transport across the emitter interface is to distinguish between the nonlinearity characteristic of the specific mechanism and the nonlinearities inherent to the DC operation of the bipolar transistor. The inherent nonlinearities, which commonly influence the measurement results obtained using the popular open-collector method for characterization of r E , are due to the Kirk effect and the substrate bias [16,17]. In this work, the nonlinear I-V characteristics associated with transport across the polysilicon emitter interface are extracted based on correction of the standard open-collector method.…”