OT: SiC Radio for Venus lander

Rodney Brown rdbrown0au at gmail.com
Sat Jul 10 07:58:40 CDT 2021


Alan Mantooth, Carl-Mikael Zetterling and Ana Rusu (28 April 2021)
"The Radio We Could Send to Hell: Silicon carbide radio circuits can 
take the volcanic heat of Venus" IEEE Spectrum
https://spectrum.ieee.org/semiconductors/materials/the-radio-we-could-send-to-hell

"The average surface temperature on Venus is 464 °C, the atmosphere is 
dense with highly corrosive droplets of sulfuric acid, and the 
atmospheric pressure at the surface is about 90 times that of Earth."
(Teflon melts at 327 °C)

The following thesis describes the Vulcan II chip mentioned a bit more
Benavides Herrera, Maria Raquel, "An RS-485 Transceiver in a Silicon 
Carbide CMOS Process" (2018).Theses and Dissertations 3067

"The RS–485 was designed in a 1.2 μm SiC CMOS process technology 
developed by
Raytheon Systems Limited (UK) called High Temperature Silicon Carbide 
(HiTSiC®).
The components available in this process include: NMOS and PMOS devices,
on-chip resistors, diodes, and capacitors.
The process key features are given below:
• 4H-SiC process
• N-type substrate
• Supply voltage of 15 V
5• Single metal layer, two layers of polysilicon (one being high sheet 
resistance poly)
• Operating temperatures greater than 300°C" ...
---
In 1988's 1.2μm CMOS process the MIPS R3010 floating-point coprocessor 
was about
75,000 transistors on an ~8mm x 8mm die.
Are there markets for SiC CMOS devices with large transistor counts?

Watching Curious Marc's video mentioning Triton missile/Saturn V bit-serial
computer implementations, reminded me of:

Olof Kindgren (2019) Bit by bit - How to fit 8 RISC-V cores in a $38 
FPGA board
https://riscv.org/wp-content/uploads/2019/06/12.15-SERV-Zurich-Copy.pdf
https://github.com/olofk/serv "SERV is an award-winning bit-serial 
RISC-V core" (RV32I)

(Not an engineer - guessing)
If process limits mean large SiC memories are unlikely, what other 
technologies
would work in the 400–500°C temperature range? Magnetic bubble memory? 
Twistors
if threading cores automatically remains infeasible?
For cameras could you build vacuum tube sensors containing SiC devices 
if useful?




More information about the cctech mailing list