A new method for determination of PAD capacitances for GaAs HBTs based on scalable small signal equivalent circuit model. (December 2018)

• Record Type: Journal Article
• Authors: Zhang, Ao; Gao, Jianjun
• Is Part Of: Solid-state electronics. Volume 150(2018)
• Page Start: 45
• Page End: 50
• Publication Date: 2018-12
• Subjects: HBT -- Equivalent circuits -- Parameter extraction -- Small signal model -- Scalable model; Semiconductors -- Periodicals; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.sse.2018.10.005
• Languages: English
• ISSNs: 0038-1101

Abstract

Highlights: No simplifying assumptions or test structures are required. The three scalable HBT devices with same pad structures are employed to determine base parasitic capacitances. This method is based on a scalable small signal equivalent circuit model under zero bias condition. The distribution effects of base and collector feedline have been taken into account. Abstract: A new direct extraction method to determine the parasitic capacitances for HBTs is presented in this paper. The main advantage is that base parasitic capacitance Cpb can be extracted by using three different size HBTs with the same pad profile. This method is based on an improved small-signal model, which takes into account the distribution effects of the base and collector feedlines. Good agreement is obtained between the measured and modeled results for the 1 × 3 × 12 μm 2, 2 × 2 × 20 μm 2 and 1 × 3 × 40 μm 2 (number of emitter fingers × emitter width × emitter length) GaAs HBTs up to 40 GHz.