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

"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 
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://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 
would work in the 400–500°C temperature range? Magnetic bubble memory? 
if threading cores automatically remains infeasible?
For cameras could you build vacuum tube sensors containing SiC devices 
if useful?

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