Heat treatment, also known as annealing, is a common step in the semiconductor fabrication process. A buildup of radiation-induced localized charge within the semiconductor and insulator alters local field distribution, threshold voltage, and leakage current. NASA's patent-pending technology implements an annealing process on a system level directly on a chip for annealing defects and improving device performance with heating done in the laboratory.

Left: (a) Heater die stacked version and (b) monolithically integrated heater version. Right: (a) Schematic illustration of self-healing architecture and (b) schematic and images of the fabricated chip.

The annealing may be performed inside an oven or upon a hotplate. A sys-tem-on-microheater provides defect annealing capability for recovering bulk trapped charges and interface states. The healing starts simply by heating the chip in a process that can be compared to that of a human's immune system — something capable of detecting and quickly responding to any number of possible assaults in order to keep the larger system working optimally.

A microheater is monolithically integrated on the backside of a generic Complementary Metal Oxide Semiconductor (CMOS) chip for an on-chip annealing system (figure, left (b)). Compared to a stacked microheater, the monolithic integration reduces the die profile that accordingly enhances the heating power efficiency and heating/ cooling rates, which was verified experimentally and numerically. The self-healing microheater is controlled by a temperature feedback circuit to maintain the desired temperature.

All circuits under the treatment are unbiased in order to avoid any side effects on normal devices. A control circuit block is programmed to monitor a device parameter shift, such as the threshold voltage on the same chip, in order to determine the need for treatment. A control circuit triggers the micro hotplate and senses the temperature to adjust the target temperature and duration. The microheater and the system-on-chip are fabricated separately and stacked into a single package that can be implemented on any arbitrary commercial off-the-shelf device as a generic approach.

NASA is actively seeking licensees to commercialize this technology. Please contact the Ames Technology Partnerships Office at This email address is being protected from spambots. You need JavaScript enabled to view it. or 855-627-2249 to initiate licensing discussions. Follow this link here for more information.