0.6 eV InGaAs/InPAs double heterostructure n/p/n tunnel junction monolithic interconnected modules (TJ‐MIMs) having p‐type bases doped uniformly at 2×1017cm−3and inhomogeneously graded from 4×1016cm−3to 4×1017cm−3(10:1 doping ratio) were grown, processed, and characterized. The electrical performance of the devices with inhomogeneously graded bases was higher than that of the uniformly doped case due to the built‐in electric field in the base region, making QEintand JSClarger. The free carrier absorption increased due to the relatively higher doping levels for the linearly doped case but remained unchanged for the exponential profile. Therefore, results showed that exponentially grading the base p‐type doping increased the MIM performance by ∼ 8&percent; (relative). © 2003 American Institute of Physics