Silicon-Germanium Integrated Electronics for Extreme Environments Applied to the Design of a Lunar Hopper Presentation to Leora Peltz (Boeing Phantom Works, Huntington Beach CA, USA) leora.peltz@boeing.com, 001-(714)-896-3186 John D. Cressler (Georgia Institute of Technology, Atlanta USA) cressler@ece.gatech.edu, 001-(404) 894-5161 Mohammad Mojarradi (Jet Propulsion Lab/Caltech, Pasadena CA USA) Mohammad.M.Mojarradi@jpl.nasa.gov, 001-(818) 354-0997
Rationale Lunar Prospector and Clementine have detected evidence from Neutron Spectrometry that suggests the existence of large amounts of hydrogen possibly ice water - in dark craters near the north and south poles of the Moon. Shackleton Crater, near South Pole of the Moon NASA Lunar Prospector, Clementine. To explore and utilize in-situ resources, such as possible ice in dark Lunar craters (e.g. Shackleton at the Lunar South Pole), we need to develop instrumentation that can operate at cryogenic temperatures, down to 43K. Ref: TEMPERATURE MODE IN COLD TRAPS ON THE MOON. E. A. Kozlova Sternberg State Astronomical Institute, 119899, Moscow, Russia; katk@sai.msu ru.
Overview of Silicon-Germanium (SiGe( SiGe) ) Integrated Electronics for Extreme Environments The Problem We Are Solving: We are developing low-cost electronics to operate in the low temperature environments. For example, Lunar missions environments expose unheated electronics to a range from +120C to -180C (day to night), and the night-time temperature lasts for 14 days. Also, the environment in dark polar craters is as low as -230C. We will create reconfigurable and modular distributed electronics that will operate in these extreme conditions without warm boxes. How Is It Done Today?: Current electronics require thermal protection ( warm boxes ), increasing system power drain, size, mass; this mandates centralized architecture, which impacts negatively on safety and reliability. The Novelty of Our Approach: We will exploit the unique properties of commercially-available (IBM) silicon-germanium integrated circuit technology; SiGe devices operate down to deep cryogenic temperatures, and have a built-in radiation tolerance; SiGe offers high integration capability (analog + digital + RF functions on the same chip). Leora Peltz Dec. 21, 2005
Overview of Silicon-Germanium (SiGe( SiGe) ) Integrated Electronics for Extreme Environments The Risks And Payoff Of Our Project: Payoffs: Electronics components that can be distributed and operate under extreme environments without a warm box will lead to flexibility in form factor; reduced weight, power, and launch mass; improved safety and reliability improved performance; leading to reduced cost. Risks: Developing new modelling and circuit design principles for extending and validating the current commercial SiGe design technology to new temperature limits, down to -230 C. How Will We Measure Our Success?: We will demonstrate to TRL-5 that SiGe provides reliable, functional packaged electronic components that meet system requirements down to -230C. Who Will Care if We Succeed?: Lunar, Mars, and Outer Planet exploration missions will benefit from modular, reusable, more reliable, lower cost electronic systems. This includes unmanned rovers, remote vehicles, landers, hoppers, subsurface devices, habitats, and space orbiting modules. Leora Peltz Dec. 21, 2005
Existing Technologies - At die temperatures of 250K, wear-out failure mechanisms of Si are diminished. - Si devices cooled to 230K function at enhanced power levels, pllied in vapor compression refrigeration - Cryogenic computers are fact and efficient, at 220K -- Ge devices can operate at 43K, but the fabrication process is more difficult - Low Frequency Noise versus Temperature Spectroscopy of Si and Ge JFETs - V. Grassi, C. Colombo, and D. Camin (Dell'Universita and INFN) - Transient Phenomena during the Self-Heating of Silicon Devices Operating at Low Temperatures - F.J. De la Hidalga (Instituto Nacional de Astrofisica) and M.J. Deen (McMaster University) - Carrier Freeze-out and Relaxation Effects in CMOS N-channel MOSFETS at Cryogenic Temperatures Under Dynamic Operating Conditions ref: G. Oleszek (University of Colorado) - The Impact of the Drain Saturation Voltage on the Multiplciation Current Modeling of the MOSFETs at Liquid Helium Temperatures - C. Claeys and E. Simoen (IMEC)
Keeping Warm Is Inefficient Ambient environment 43K Electronics Batteries At 43K, electronics may use up to 30% of battery energy for keeping warm high insulation needed to keep heat inside Battery energy needed to heat the two warm boxes. Using RTG for energy, Involve high costs for launch safety procedures. Ambient environment 400K Electronics Batteries low insulation needed to prevent heat buildup
The SiGe Advantages SiGe devices can operate down to cryogenic temperatures, and have built-in radiation tolerance. SiGe offers high integration capability (analog + digital + RF functions on the same SiGe chip). Image from the cover of the SiGe book by John Cressler SiGe HBT and CMOS devices are functional down to 43K
Our R&D Activity Technology Challenges for operation over almost 400K temperature range: Design rules for SiGe circuits. Extended models of SiGe devices. Reliable packaging. Device reliability and ageing mechanisms. We are developing low-cost electronics to operate directly exposed to extreme environments down to 43K. Our targeted design is a Remote Electronics Unit (REU), which can provides data acquisition and control for various applications. We exploit the unique properties of commercially available SiGe, to develop reconfigurable / modular distributed electronics that can operate in extreme environments without warm boxes. World-class team of University / Industry experts in SiGe Devices, circuits, packaging, maturation
from System-on-a-chip to Lunar Hoppers Initial lunar lander trajectory into polar lunar crater Lunar lander trajectory from polar lunar crater floor to nearby secondary landing site Precision Landing & Hazard Avoidance Technology Program Exploration Clipper Distributed data acquisition and control, with SiGe REU. REUs can be located proximally to sensors and actuators. REUs enable efficient Fault Tolerant Adaptive Control of the vehicle. REUs simplify Fault Detection and Identification, and optimal management of Fault-Tolerant Actuators.