Dr. Fujio MasuokaDr. Fujio Masuoka (1943 - )

Inventor, Flash Memory


Each time you slide a flash memory card into a digital camera, or a thumb drive into a USB jack, sync your music to a digital music player, or store data on a tablet PC, thank Dr. Fujio Masuoka, who invented flash memory.

Masuoka was born May 8, 1943, in Takasaki City, Gunma, Japan. When he was 10, his mother encouraged him to study mathematics and hired a private teacher. By the time he was 12, Masuoka had mastered advanced mathematics. In high school, Masuoka concentrated on theory, believing that advances in technology or electronics were achieved only through theoretical work. As a result of his studies, Masuoka also developed a deep understanding of economics and law.

He received his Bachelor of Science, Masters of Science and PhD in electrical engineering from Tohoku University in 1966, 1968 and 1971, respectively. Soon after graduating, Masuoka joined Toshiba Research and Development Center in April 1971.

Three months into his new job, Masuoka’s boss, Dr. Yoshiyuki Takeishi, showed Masuoka Intel’s Ultraviolet Electrically Erasable Programmable Read Only Memory (UV EEPROM), which was announced a few months earlier. Masuoka studied the Intel technology for two months and discovered a new structure, a stacked gate avalanche injection type MOS read-only memory (SAMOS), which became Masuoka’s first patent in 1972.

Between 1972 and 1984, Masuoka made other significant memory breakthroughs, pairing a dynamic memory cell with a double poly-silicon structure. In 1977, he moved to Toshiba’s semiconductor division, where he developed 1 Mbit DRAM.

Masuoka later transitioned to Toshiba’s memory product engineering division in 1980 to begin his work on developing flash memory. He then shifted to Toshiba’s memory design engineering division in 1984, where he perfected and patented NOR flash memory. He presented his findings at the International Electron Device Meeting (IEDM) in San Francisco. A year later, he progressed to 256 Kbit flash memory.

In April 1987, Masuoka returned to the Toshiba research and development center, where he began to successfully develop more advanced NAND-type flash memory. Despite his breakthroughs, flash was not yet ready for commercialization. What slowed Masuoka down was not technology, but money.

In order to create and manufacture a commercial pre-fabricated 4 Mbit flash memory chip, Masuoka needed to develop a mask to serve as a high-tech stencil to project the various circuit patterns on each layer of a microprocessor. But the cost estimate to create a mask was 10 million yen, which Toshiba was initially unwilling to invest. Masuoka convinced Toshiba’s consumer electronics research executives that a 4 Mbit flash memory chip could be used to create a consumer-ready digital camera with the flash memory serving as “digital film.” With funding from the consumer electronics division, Masuoka continued his development and presented the 4 Mbit NAND-type flash memory at the International Solid-State Circuits Conference (ISSCC) in New York City in 1989.

A Toshiba USB Flash Drive

In 1994, Masuoka joined Tohoku University where he was a professor for 13 years before being appointed Professor Emeritus of the university’s Research Institute of Electrical Communication.

For his pioneering work on flash memory, Masuoka has been presented with numerous honors and awards in Japan including the inaugural Watanabe Prize in 1977 and the National Invention Award in 1980. In 2007, Masuoka was awarded the Medal with Purple Ribbon from Emperor Akihito.