Kan Yasui

Determination of Lateral Charge Distributions of Split-gate SONOS Memories Using Experimental Devices with Nanometer-size Nitride Piece

Lateral charge distribution in nitride of split-gate type semiconductor-oxide-nitride-oxide-semiconductor (SONOS) memories has been determined by well-controlled experimental devices in which nanometer-size nitride piece was located at various positions for monitoring trapped charge. We found that electron distribution is created by two different hot-electron-injection mechanisms. Based on this new finding, the way to improve the matching of electron and hole distributions is investigated.

Demonstration and analysis of high resolution differential read-head

We investigated properties of a differential read-head focusing on resolution, output signal, and bit error rate (BER) through experiments and calculations. We successfully observed particular waveforms of the differential head. The fabricated differential heads showed much higher resolution and better BER than conventional heads. Through measurements and calculations, we clarified that as gap-length (GL) between two spin-valves decreases, the resolution for the differential head increases, but the output signal decreases. Accordingly, the differential head has optimal GL to achieve the best BER. The optimal GL is almost the same as the shortest bit length. We also clarified that a calculated differential head with optimized GL has better BER than a conventional head with a shield-gap length of 20 nm, especially at higher linear density. Therefore, the differential head is one of the candidates for reader structures for high-areal-density hard disk drives.

A Highly Efficient 3.3-kV SiC-Si Hybrid Power Module with a Novel SiC JBS Diode and a Si Advanced Trench HiGT

A 3.3-kV SiC-Si hybrid module, composed of a low-forward-voltage (VF) SiC junction-barrier-Schottky (JBS) diode and a low-saturation-voltage VCE(sat) Si trench IGBT was fabricated and demonstrated highly efficient operation.