Prolonged silicon carbide integrated circuit operation in Venus surface atmospheric conditions

Philip G Neudeck,Liangyu Chen,Leah M Nakley,Gary W Hunter,Roger D Meredith,David J Spry

doi:10.1063/1.4973429

Abstract

The prolonged operation of semiconductor integrated circuits (ICs) needed for long-duration exploration of the surface of Venus has proven insurmountably challenging to date due to the ∼ 460 °C, ∼ 9.4 MPa caustic environment. Past and planned Venus landers have been limited to a few hours of surface operation, even when IC electronics needed for basic lander operation are protected with heavily cumbersome pressure vessels and cooling measures. Here we demonstrate vastly longer (weeks) electrical operation of two silicon carbide (4H-SiC) junction field effect transistor (JFET) ring oscillator ICs tested with chips directly exposed (no cooling and no protective chip packaging) to a high-fidelity physical and chemical reproduction of Venus’ surface atmosphere. This represents more than 100-fold extension of demonstrated Venus environment electronics durability. With further technology maturation, such SiC IC electronics could drastically improve Venus lander designs and mission concepts, fundamentally enabling long-duration enhanced missions to the surface of Venus.

Highlights

We decided to subject other chips diced from the same prototype IC wafer to electrical testing in simulated Venus surface atmospheric conditions inside the National Aeronautics and Space Administration (NASA) Glenn Extreme Environments Rig (GEER).[27]
Ring oscillator chips were selected for the first such test, as these ICs can be operated using the fewest number of wires, are a recognized standard for logic IC demonstration, and provide harmonic output signals that can be detected in frequency spectrum even in the presence of substantial expected electrical noise and output signal path attenuation
Two NASA Glenn fabricated SiC JFET ring oscillator ICs residing on separate chips were selected for testing in GEER: a 3-stage ring oscillator and an 11-stage ring oscillator that are further described in the supplementary material and elsewhere.[24,25,26,28]

Summary

Introduction

(Received 23 September 2016; accepted 16 December 2016; published online 27 December 2016) Functioned for more than 1000 hours (41.7 days) at 500 ◦C in Earth-atmosphere oven-testing.[24,25,26] Given these promising results, we decided to subject other chips diced from the same prototype IC wafer to electrical testing in simulated Venus surface atmospheric conditions inside the NASA Glenn Extreme Environments Rig (GEER).[27] Ring oscillator chips were selected for the first such test, as these ICs can be operated using the fewest number of wires (one signal output in addition to +VDD, GND, and -VSS chip DC power inputs), are a recognized standard for logic IC demonstration, and provide harmonic output signals that can be detected in frequency spectrum even in the presence of substantial expected electrical noise and output signal path attenuation.

Results

Conclusion