Technology Directions at ISSCC 2014
February 12, 2014, ISSCC, San Francisco—New materials and technologies are starting to move beyond the lab into new applications. The different semiconductor materials are being deposited on many types of substrates and the component libraries are now rich enough to make microprocessors and PROMs and well as display drivers and analog circuits.
Kris Myny from Imec constructed an 8-bit microprocessor hybrid oxide-organic complementary technology with inkjet-printed p2rom memory. The processor can execute 2.1k instructions per second with complementary devices on a plastic substrate. Standard cell delays are in the 10’s of microseconds with a supply at 10V. The print programmable ROM uses conductive material in ink drops to short connections with up to 16 inputs. The number of drive TFTs is configured in a post-fabrication step to address loading issues.
Hiroshi Fuketa from the University of Tokyo added ESD tolerance to a flexible wet sensor. The applications are for disposable, external sensors without batteries. The circuits are powered through a 13.56MHz magnetic resonance loop and use all organic semiconductors. The inputs and outputs are ESD protected to 2kV by organic Schottky diodes.
Not everything is for miniaturization. Shuichi Nagai from Panasonic is working on GaN power switching chips for motor drive and other high-power applications. An inverter-based converter uses AC to DC to AC to drive a synchronous AC motor. A 3 X 3 converter matrix using bidirectional power switches drives the multi-phase motor.
To overcome the shortcomings of traditional isolated drivers that consume high power themselves, multiple control lines, and many discrete components, the controls and isolation come from microwave isolated control. The microwaves also supply the power to drive the motor. The GaN bidirectional switches handle 600V at 10A in the integrated RF and power device. The gate drive for the power switches is a separate RF link of similar design.
Junghyup Lee from the Institute of Microelectronics in Singapore considers the body as a signal conduit instead of RF or wearable devices. The use of the body eliminates antenna and is immune t facing effects for wearable medical devices. A high-efficiency wideband transmitter can send 60Mb/s in a 3:1 Walsh code, which is helped by the band pass filter characteristics of the body conduction channel.
The resulting chip uses 1.85mW in transmit and 9mW in receive modes. Injection locking receives data to recover the clock. The design has no PLLs nor crystal oscillators. Images transferred through the body show good fidelity and low noise. The transmit sections achieves 31pJ/b while the receiver uses 150pJ/b.
Takeshi Aoki from the Semiconductor Energy Laboratory investigates normally off computing and an application in FPGA that stops tasks based upon context. The material of choice for this effort is crystalline InGaZnO. Each programmable logic element includes routing switches, look-up table, carry logic, and registers. A 2-phase non-overlaping clock enables a stable clocking scheme that is coupled with the context switching logic to minimize power. Even with the context switches, the non-volatile registers can handle high-speed data store and load functions.
