Complementary bipolar (CBi) inverters on scaled down self-aligned transistors with highly-doped bases for advanced high-speed low-voltage low-power deep-submicron ULSI are considered and studied using a simulator PSPICE. A novel symmetrical transistor structure (STS) with undoped (lightly-doped) active base and nanometer regime, that can function as complementary n-p-n and p-n-p devices for CBI inverters at ultra-reduced supply voltages V-EE, V-EE=0.1-0.5 V, is investigated and simulated. It is shown that numerical mixed 2D-device-circuit simulator (DCSIM) for personal computer gives accurate knowledge of the static and dynamic properties of upward and downward self-aligned STS and CBi inverters eliminating the intermediate nonaccurate procedure of model electrical parameter extraction. This paper presents 2D numerical device-circuit simulations of the bipolar nanostructures and push-pull inverters on complementary STS with undoped active bases in ultra-low-voltage regime providing a high degree of integration, extremely high intrinsic speed and sufficiently high driving capacity. The switching problems for high-speed low-power low-action operations and optimization of sub-0.5 V Cbi inverters are studied.