Formation of location-controlled crystalline islands using substrate-embedded seeds in excimer-laser crystallization of silicon films

Abstract

Single-crystal thin-film transistors on nonrefractory materials such as glass can be realized if monocrystalline islands of sufficient sizes can be grown at a predetermined position. By artificially controlling the super-lateral growth phenomenon observed in excimer-laser crystallization, this could be achieved. In this letter, we present such a method in which the silicon filling of a very small indentation fabricated in the substrate will act as a seed for lateral growth of large grains. When the melt is deep in these indentations, lateral growth is preceded by a vertical growth phase during which grains become occluded, so that a high yield of monocrystalline islands is obtained.

Dependence of Single-Crystalline Si TFT Characteristics on the Channel Position Inside a Location-Controlled Grain

“…The TFTs used in this experiment were fabricated with the -Czochralski process [8]; a schematic diagram of the c-Si TFT is shown in Fig. 1.…”

“…We controlled the position of the grain by modifying the substrate with conventional photolithography rather than by spatially modifying the incident laser energy density. The -Czochralski (grain filter) process [8] provides a precise way to control the position of the grain in excimer laser crystallization. The c-Si TFTs fabricated inside a location-controlled grain by this -Czochralski (grain filter) process showed on average a of 430 cm V s [9].…”

Design and fabrication of single grain TFTs and lateral photodiodes for low dose x-ray detection

“…A low-temperature process, based on the μ-Czochralski technique with excimer-laser crystallization of a-Si film, has been developed in TU Delft and used to control the positions of the islands. The proposed X-ray image sensor is a solution to the lag problem and frequency limitation of a-Si TFT via high mobility [3] while achieving a detection area for chest radiography without the tiling process which causes data lost at the connection of the detector arrays. …”

SPICE Modeling of Single-Grain Si TFTs using BSIMSOI

“…Single Grain Thin-Film Transistors (SG-TFTs) fabricated inside a location-controlled grain by µ-Czochralski technology using an excimer laser have reached Silicon-onInsulator (SOI) performance despite low temperature fabrication (< 350 °C) process (1)- (3). Digital circuits as well as analog and RF circuits could be integrated with display or into vertical direction for applications of Flexible-Electronics or 3D ICs, respectively.…”