I have written about Sidense before, but last week at the TSMC Open Innovation Platform Forum, I had a chance to hear a talk by, and have lunch with Betina Hold Director of R&D at Sidense. Here is what I learned.
Sidense has been focusing on the growing market in what they like to call the smart connected universe. It is best to think of this as the union of mobile, IoT, wearables, medical, industrial and automotive. Incidentally Automotive was a hot topic at the OIP Forum.
However, getting back to our main topic, all of these applications have a need for non-volatile memory (NVM). In many cases the need is for secure and reliable storage for device ID’s, security codes, trim information and a variety of other write-few, read-many pieces of data. This can even extend to boot code.
This is a perfect application for one time programmable(OTP) NVM. Even if you need to make multiple writes, the NVM controller or system firmware can make it look like “few times programmable” (FTP) memory. OTP-NVM has several distinct advantages that make it a clear choice for chip design. The most obvious is that it requires no special masks nor any changes to the process at all. The Sidense 1-T solution uses the process and PDK designers are already using for their circuits.
Sidense has working silicon from 180nm down to 16 Fin FET. During her talk, Betina pointed out that the underlying OTP-NVP technology they use has actually improved with FinFET devices. They are seeing 100,000X difference between the read currents in 0 and 1 states with 16nm. Sidense is seeing that the leakage current in Fin FET devices has improved >10X relative to 28nm.
Sidense has been very successful at reducing the power requirements for its OTP. Typically, only the chip’s VDD is needed and no external or higher voltage supplies are required. The high read margins help reduce the power needs. Sidense also offers interfaces for sub-threshold operating voltages that are being targeted in new processes. This will further help reduce operating power.
The thing that Betina spoke about most passionately was how Sidense OTP NVM addresses security. She pointed out that their CTO Wlodek Kurjanowicz came from Chipworks, where he became very familiar with techniques used to reverse engineer circuits. Sidense works hard to ensure that data stored on their NVM-OTP cannot be hacked or compromised.
Hackers will go to great lengths to reverse engineer or even attempt to alter stored data and code. Sidense OTP NVM uses fully differential data storage, with complementary logic and bit cell structures to avoid any power signatures based on read values. Also, there are built in protections against tampering with clocks, operational voltage and even hacking attempts through lowering temperature.
The bit cells are also difficult to physically reverse engineer. There is no discernible physical difference between a 1 and a 0. Additionally, the hard IP routing for the OTP-NVM is designed to inhibit access if some of the metal is removed. All of this is very important because gaining physical access to connected devices that may have the ability to threaten larger secure systems is easier than ever. No longer can security depend on keeping hackers away from physical systems.
Even though I am very familiar with NVM-OTP, I learned a lot about the advantages of using them and how Sidense endeavors to ensure an extra level of security. For more information about Sidense, follow this link.