Toshiaki Miyajima

Formation of Double Layered SOI With Controlled Crystal Orientation

For the crystal orientation control of multi-layered SOI (Silicon on Insulator) by the laser recrystallization technology, the shape and size of seeds were investigated. By utilizing dot seeds less than 3μm square instead of a line seed, the crystal orientation control of a SOI layer was successfully realized without causing evaporation of silicon. Moreover, the dot seed method enabled us to control the crystal orientation of multi-layered SOI by virtue of small heat flow through seed regions. In the mean time, it was proved that the SOI crystal orientation gradually rotated as the crystal propagated away from the seeds and that the degree of rotation in the second SOI layer was smaller than that in the first one.

SOI photodiode array stacked on VDMOS for optical switching

This paper describes the first development of the single chip optical switching device for optical coupling MOS relay by SOI technology. The device is constructed with a laser recrystailized SOI layer as a photoelectric element, which is fabricated in the upper layer in the device and shades the power MOSFET fabricated in the lower layer. On illuminating the device, the power MOSFET can be switched on Accordingly, an optical switching MOSFET with the function of a photodiode and a MOSFET is realized as a single chip device.

Three Dimensional Thermal Analysis for Laser Annealing and Its Application to the Design of the SOI Structures

Laser annealing (LA) has recently been used to obtain recrystallized silicon fifms, where 3D devices could be realized. The precise process control required in their applications encourages the construction of a computer model for the temperature rise canse-d by LA. We simulated the stationary temperature profiles induced by a movi-ng cw laser beam in mul-ti-layered SOI structures. In order to improve the crystal quality, we proposed the SOI structures capped with polysilicon and applied this simulation to the design of these structures. They forced single nucleation and the qrain boundaries would be located beneath the outside of the polysilicon encapsulation.