Physical, small-signal and pulsed thermal impedance characterization of multi-finger SiGe HBTs close to the SOA edges

Abstract

A thermal impedance model of single-finger and multi-finger SiGe heterojunction bipolar transistors (HBTs) is presented. The heat flow analysis through the device has to be considered in two diffusion parts: the front-end-of-line (FEOL) diffusion and the back-end-of-line (BEOL) diffusion. Therefore, this new thermal impedance model features multi-poles network which has been incorporated in HiCuM L2 compact model. The HiCuM compact model simulation results are compared with on-wafer low-frequency S-parameters measurements at room temperature highlighting the device frequency dependence of self-heating mechanism. The simulation results are also compared to pulse measurements to improve reliability analysis.

Towards Monolithic Indium Phosphide (InP)-Based Electronic Photonic Technologies for beyond 5G Communication Systems

“…On the contrary, for an angle θ > θC, the heat flow is first blocked by the mesa edge, thus leading to a uniform heat diffusion in one subsection (see Figure 9b), followed by a pyramidal diffusion pattern toward the substrate. Based on previous works [14,19], the heat diffusion angle is found to be always lower than 65°, leading to the heat-flow scenario depicted in Figure 9a. Hence, for the rest of the thermal modeling approach, scenario (a) was considered.…”

“…The reduction in the transit time with emitter width scaling has been observed at high current densities, which can be attributed to a pronounced collector current spreading in smaller emitter dimensions [34], leading to larger critical current and smaller transit time values. Small emitter dimension particularly poses a challenge to maintain an acceptable current gain (β), of which rather low (15)(16)(17)(18)(19)(20) values have been reported for the 0.13 µm InP HBT process [1,33]. On the other hand, the prediction for the current generation shows an extrapolated current gain of 25-30 for the 0.13 × 2 µm 2 DHBT (Figure 22b).…”

Static Thermal Coupling Factors in Multi-Finger Bipolar Transistors: Part I—Model Development

“…In order to calculate the peak junction temperature of the heating finger in case of ST isolated multifinger structure, one can use (6) by sectioning the full vertical region into three parts as carried out in [13]. The value of spreading angle within STI volume was chosen as 35 • to consider the evident heat confinement at close proximity to the heat source [26][27][28]. For the substrate region below the ST, spreading angle was kept at 48 • following the ones used in the structure with no-trench isolation.…”

A physical and versatile aging compact model for hot carrier degradation in SiGe HBTs under dynamic operating conditions

“…As the physical system can only be considered for one dimension, an R-C ladder network is used. This architecture is commonly used for thermal diffusion modeling [16]. It is made of N resistors and N capacitors followed by an optional terminal resistor (of conductance G) depicted in Fig.…”