Characteristics of GaAs spike doped collectors

Spike-doped collector designs have recently been studied in both Si BJT and GaAs HBTs as a way to improve the device linearity while still maintaining ruggedness. In this work, we present and discuss - for the first time - the very interesting output characteristics of these devices (unique Ic-Vce curves) and how they are influenced by the device design. We also explore the improvement in cut-off frequency versus current and application of these devices to actual power amplifiers and the resulting changes in ruggedness.