Steep-subthreshold-slope Transistors for Electronics with Extremely-Low Power (STEEP)
Abstract
(U)The Steep-subthreshold-slope Transistors for Electronics with Extremely-low Power (STEEP) program goal was to develop revolutionary transistor technologies, which enabled devices to be operated at voltages as low as 0.2 V without loss in performance (defined by available drive current). The approach was to develop novel transistors with sub-threshold “turn-on” slopes as sharp as 20 millivolt (mV)/decade while maintaining excellent current drive characteristics. This program mainly focused on developing band-to-band tunneling transistors that will be operated at low bias voltages with high saturation current and low leakage current. In addition, associated device models were developed in the program to enable novel ultra-low power circuit designs. At the end of the program, complex demonstration circuits achieved significant power savings, both active and standby, of at least twenty-five times. The STEEP transistors utilized the mechanism of gate controlled modulation of the energy band alignment between the conduction and valence bands of a band-to-band-tunneling device. The key technical challenges of the program included (1) achieving steep sub-threshold slope over many decades of current, (2) developing CMOS compatible fabrication flow, (3) developing novel circuit designs accommodating asymmetric source-drain doping, (4) demonstrating abrupt doping profiles at tunneling junctions, and (5) integrating silicon-germanium (SiGe), germanium (Ge), or group III-V material in the transistor structures to facilitate the required tunneling currents. The STEEP program started with the development of transistors with less than 30mV/dec of sub-threshold slope and then proceeded to demonstrate the integration of these devices into logic circuits using an eight inch wafer technology. Finally, the STEEP program focused on the yield improvement of a complex ultra-low power static random access memory (SRAM) circuit.
Document Details
- Document Type
- Accomplishment
- Publication Date
- Oct 01, 2011
- Source ID
- dbfb482b131cbe6f787bf4a46c963a6c
Related Documents
- Root: ELECTRONICS TECHNOLOGY