Hydrogen as the cause of pit formation during laser recrystallization of silicon‐on‐insulator films

1989 ◽  
Vol 66 (9) ◽  
pp. 4444-4455 ◽  
Author(s):  
G. J. Willems ◽  
H. E. Maes
1984 ◽  
Vol 35 ◽  
Author(s):  
A.J. Auberton-Herve ◽  
J.P. Joly ◽  
J.M. Hode ◽  
J.C. Castagna

ABSTRACTSeeding from bulk silicon (lateral epitaxy) has been used in Ar+ laser recrystallization to achieve subboundary free silicon on insulator areas. On these areas C.MOS devices have been performed using almost entirely the standard processing steps of a bulk micronic C-MOS technology. n -MOS transistors with channel length as small as 0.3 um have shown very small leakage currents. This is attributed especially to the lack of subboundaries. A 40 % increase in the dynamic performances in comparison with equivalent size C-MOS bulk devices has been obtained (93 ps of delay time per stage for a 101 stages ring oscillator with 0.8 μm of channel length). This is the best result presented so far on recrystallized SOI. No special requirements are needed in the lay out of the circuit with the chosen seed structure. Furthermore an industrial processing rate for the laser recrystallization processing has been achieved using an elliptical laser beam, a high scan velocity (30 cm/s) and a 100 μm line to line scan step (a 4' wafer in 4 minutes).


1985 ◽  
Vol 53 ◽  
Author(s):  
C. H. Ting ◽  
W. Baerg ◽  
H. Y. Lin ◽  
B. Siu ◽  
T. Hwa ◽  
...  

ABSTRACTA seeded channel approach was developed to avoid the short comings of the conventional SOI structure such as grain or sub-grain boundaries in the channel region, floating substrate effects, etc. In this approach, the gate of each FET is located above its own seed window to insure that single crystalline material is obtained for the channel region. The source and drain regions, however, are located in the recrystallized silicon over Si02 for improved isolation and minimizing junction capacitance. Recrystallization was obtained in 4" silicon wafers by using an Ar laser and a computer controlled X-Y stage with heated substrate holder. Problems encountered in laser recrystallization, such as, reflectivity variations over seed and SOI regions, surface ripples, pittings, etc., were eliminated by optimizing the thin film thickness of the isolation oxide, polysilicon, and the capping oxide. This technology was used successfully to fabricate FET devices using a standard production n-MOS process. Good device characteristics were obtainred using 400Å gate oxide and channel length ranging from 1um to 50um. The measured electron mobility in the channel region is, however still lower than the ideal bulk values.


1990 ◽  
Vol 201 ◽  
Author(s):  
E. Cortesi ◽  
F. Namavar ◽  
R. F. Pinizzotto ◽  
H. Yang

AbstractWe have studied Separation by IMplantation of OXygen (SIMOX) processes using very high dose rates (40–60 μA/cm2). For a dose of 4 × 1017 O+/cm2 at 160 keV, the structure formed by implantation at 50 μA/cm2 is very similar to that associated with lower dose rates. The same dose implanted at a dose rate of 60 μA/cm2, however, results in the formation of pits in the silicon surface as well as a somewhat different oxide structure. Implantation through a surface oxide layer appears to result in a structure similar to that associated with lower dose rate implantation. These and higher dose samples suggest that the threshold for pit formation is related to both dose rate and dose.


1984 ◽  
Vol 35 ◽  
Author(s):  
J.P. Colinge

ABSTRACTThere are various methods for producing device-worthy Silicon-on-Insulator films, most, however, are unsuitable for fabrication of 3D integrated structures. The laser recrystallization technique is currently the only one which has produced single-crystal devices for 3D ICs. Improvements on this technique have been such that defects such as grain boundaries can be localized and even eliminated. High speed CMOS circuits with VLSI features have been realized as well as new devices which take advantage of the 3D arrangement of vertically integrated structures. Although 3D integration is still in the early stages of development, it has already opened up new perspectives for applications such as high speed circuits, dense memories, and sensors.


1986 ◽  
Vol 74 ◽  
Author(s):  
S. Sritharan ◽  
G. J. Collins ◽  
J. Fukumoto ◽  
N. Szluk ◽  
K. M. Jones ◽  
...  

AbstractLatchup free lateral CMOS transistors with PMOS devices in the laser recrystallized silicon and the NMOS devices in the bulk silicon were fabricated. One micron thick field oxide isolates the PMOS devices in the recrystallized silicon from the NMOS devices in the bulk wafer. The seed area for recrystallization was used for the fabrication of the NMOS devices. An oxide layer of 0.1um thickness was used to protect the channel region of the NMOS devices during the laser recrystallization. The effect of this channel protect-oxide is discussed and the characteristics of the NMOS devices with and without the channel protect oxide are compared.


1985 ◽  
Vol 53 ◽  
Author(s):  
Samhita Dasgupta ◽  
Howard E. Jackson ◽  
Joseph T. Boyd

ABSTRACTLaser recrystallization of silicon on an insulating substrate has been carried out by irradiating polysilicon with both an Ar+ laser operating on all lines in the visible and a CO2 laser operating at 10.6 microns. These experiments were carried out over a variety of laser power densities and substrate temperatures. The use of the two lasers allowed for independent spatial control of temperature in both the polysilicon and the SiO2 layers and helped to reduce the strain at the polysilicon - SiO2 interface. We report the successful recrystallization of polysilicon films without substrate heating for two different silicon-on-insulator structures.


1987 ◽  
Vol 107 ◽  
Author(s):  
Toshiaki Miyajima ◽  
Hideyuki Tsuji ◽  
Masashi Maekawa ◽  
Masayoshi Koba

AbstractFor 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.


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