Stability of Silicide Films Under Post-Annealing: a Dopant Effect

AbstractThe formation of PtSi films by rapid thermal processing of e-beam evaporated Pt on <100> Si has been studied. The current study found that PtSi films have the potentially useful property of oxidizing, i.e., forming a surface layer of Si02 which may be useful for patterning. Rapid oxide formation is found with, possibly, linear growth rates when the film is doped with As to 8E15 atoms/cm2 at 80 KeV but insignificant oxidation if the film is undoped or B-doped. Rutherford backscattering analysis shows significant redistribution of the As during silicidation and oxidation with As excluded from the silicide, diffusing to the oxide and especially the oxide surface. Post-silicidation anneals have been done in a conventional tube furnace at 650ºC for up to 60 minutes and form an oxide thickness of up to 200 nm. NiSi films appear stable if Bdoped, oxidize with Ni piling up at the Si02/Si interface if undoped, and are unstable with Ni diffusing deep into the Si if As-doped.

Download Full-text

Optimization of Process Parameter and Temperature Uniformity On Wafers For Rapid Thermal Processing

MRS Proceedings ◽

10.1557/proc-387-3 ◽

1995 ◽

Vol 387 ◽

Cited By ~ 6

Author(s):

Andreas Tillmann

Keyword(s):

Standard Deviation ◽

Thermal Processing ◽

Rapid Thermal Processing ◽

Oxide Thickness ◽

Simulation Software ◽

Process Parameter ◽

Parameter Distribution ◽

Temperature Uniformity ◽

New Strategy ◽

The Impact

AbstractA new strategy based algorithm to optimize process parameter uniformity (e.g.sheet resistance, oxide thickness) and temperature uniformity on wafers in a commercially available Rapid Thermal Processing (RTP) system with independent lamp control is described. The computational algorithm uses an effective strategy to minimize the standard deviation of the considered parameter distribution. It is based on simulation software which is able to calculate the temperature and resulting parameter distribution on the wafer for a given lamp correction table. A cyclical variation of the correction values of all lamps is done while minimizing the standard deviation of the considered process parameter. After the input of experimentally obtained wafer maps the optimization can be done within a few minutes. This technique is an effective tool for the process engineer to use to quickly optimize the homogeneity of the RTP tool for particular process requirements. The methodology will be shown on the basis of three typical RTP applications (Rapid Thermal Oxidation, Titanium Silicidation and Implant Annealing). The impact of variations of correction values for single lamps on the resulting process uniformity for different applications will be discussed.

Download Full-text

Rapid Thermal Annealing and Oxidation of Silicon Wafers with Back-Side Films

MRS Proceedings ◽

10.1557/proc-470-49 ◽

1997 ◽

Vol 470 ◽

Cited By ~ 1

Author(s):

A. T. Fiory

Keyword(s):

Thermal Oxidation ◽

Sheet Resistance ◽

Thermal Annealing ◽

Rapid Thermal Annealing ◽

Temperature Control ◽

Thermal Processing ◽

Rapid Thermal Processing ◽

Oxide Thickness ◽

Back Side ◽

Control Accuracy

ABSTRACTTemperatures for lamp-heated rapid thermal processing of wafers with various back-side films were controlled by a Lucent Technologies pyrometer which uses a/c lamp ripple to compensate for emissivity. Process temperatures for anneals of arsenic and boron implants were inferred from post-anneal sheet resistance, and for rapid thermal oxidation, from oxide thickness. Results imply temperature control accuracy of 12°C to 17°C at 3 standard deviations.

Download Full-text

Improvement of oxide thickness uniformity by high then low O2 pressure oxidation in rapid thermal processing

Journal of Vacuum Science & Technology A Vacuum Surfaces and Films ◽

10.1116/1.1453455 ◽

2002 ◽

Vol 20 (2) ◽

pp. 544-548 ◽

Cited By ~ 1

Author(s):

Chao-Chi Hong ◽

Jenn-Long Chen ◽

Jenn-Gwo Hwu

Keyword(s):

Thermal Processing ◽

Rapid Thermal Processing ◽

Oxide Thickness ◽

Pressure Oxidation ◽

Thickness Uniformity

Download Full-text

Ge nanocrystals in MOS-memory structures produced by molecular-beam epitaxy and rapid-thermal processing

MRS Proceedings ◽

10.1557/proc-830-d6.2 ◽

2004 ◽

Vol 830 ◽

Author(s):

A. Nylandsted Larsen ◽

A. Kanjilal ◽

J. Lundsgaard Hansen ◽

P. Gaiduk ◽

P. Normand ◽

...

Keyword(s):

Molecular Beam Epitaxy ◽

Process Parameters ◽

Gate Voltage ◽

Thermal Processing ◽

Molecular Beam ◽

Rapid Thermal Processing ◽

Oxide Thickness ◽

Mos Capacitors ◽

Very High ◽

Ge Nanocrystals

ABSTRACTA method of forming a sheet of Ge nanocrystals in a SiO2 layer based on molecular beam epitaxy (MBE) and rapid thermal processing (RTP) is presented. The method takes advantage of the very high precision by which a very thin Ge layer can be deposited by MBE. With proper choice of process parameters the nanocrystal size can be varied between ∼3 and ∼8 nm and the area-density between ∼1×1011 and ∼1×1012 dots/cm2. The tunneling oxide thickness is determined by the thickness of a thermally grown SiO2 layer, and is typically 4 nm. C-V measurements of MOS capacitors reveal hole and electron injection from the substrate into the nanocrystals. Memory windows of about 0.2 and 0.5 V for gate-voltage sweeps of 3 and 6 V, respectively, are achieved.

Download Full-text

Optimization of Process Parameter and Temperature Uniformity on Wafers for Rapid Thermal Processing

MRS Proceedings ◽

10.1557/proc-389-275 ◽

1995 ◽

Vol 389 ◽

Author(s):

Andreas Tillmann

Keyword(s):

Standard Deviation ◽

Thermal Processing ◽

Rapid Thermal Processing ◽

Oxide Thickness ◽

Simulation Software ◽

Process Parameter ◽

Parameter Distribution ◽

Temperature Uniformity ◽

New Strategy ◽

The Impact

ABSTRACTA new strategy based algorithm to optimize process parameter uniformity (e.g. sheet resistance, oxide thickness) and temperature uniformity on wafers in a commercially available Rapid Thermal Processing (RTP) system with independent lamp control is described. The computational algorithm uses an effective strategy to minimize the standard deviation of the considered parameter distribution. It is based on simulation software which is able to calculate the temperature and resulting parameter distribution on the wafer for a given lamp correction table. A cyclical variation of the correction values of all lamps is done while minimizing the standard deviation of the considered process parameter. After the input of experimentally obtained wafer maps the optimization can be done within a few minutes. This technique is an effective tool for the process engineer to use to quickly optimize the homogeneity of the RTP tool for particular process requirements. The methodology will be shown on the basis of three typical RTP applications (Rapid Thermal Oxidation, Titanium Silicidation and Implant Annealing). The impact of variations of correction values for single lamps on the resulting process uniformity for different applications will be discussed.

Download Full-text

Impact of Patterned Layers on Temperature Non-Uniformity during Rapid Thermal Processing for VLSI-Applications

MRS Proceedings ◽

10.1557/proc-146-149 ◽

1989 ◽

Vol 146 ◽

Cited By ~ 38

Author(s):

P. Vandenabeele ◽

K. Maex ◽

R. De Keersmaecker

Keyword(s):

Thermal Processing ◽

Large Scale ◽

Rapid Thermal Processing ◽

Oxide Thickness ◽

Experimental Results ◽

Time Dependent ◽

Optical Characteristics ◽

Large Temperature ◽

Oxide Layers ◽

Patterned Wafers

ABSTRACTThe influence of patterned oxide layers on temperature non-uniformity during RTP is studied. It is shown that large temperature non-uniformities (up to 80 °C) can occur during RTP as a consequence of large scale patterns of thick oxides. The dependence of oxide thickness and pattern geometry on temperature non-uniformity over a wafer is studied. A set of simulation programs is developed to calculate the optical characteristics of a wafer inside a chamber and to calculate the time dependent temperature non-uniformities on patterned wafers. The calculated results agree very well with the experimental results. The simulation program was used to define the optimal optical conditions for RTP systems for minimal temperature non-uniformity due to patterned overlayers on Si.

Download Full-text

Residual Gases and Their Influence on Processes in the Atmospheric Rapid Thermal Processing Equipment

MRS Proceedings ◽

10.1557/proc-525-45 ◽

1998 ◽

Vol 525 ◽

Cited By ~ 1

Author(s):

Yao Zhi Hu ◽

Sing Pin Tay

Keyword(s):

Thermal Processing ◽

Rapid Thermal Processing ◽

Oxide Thickness ◽

Tank Model ◽

Process Gas ◽

Oxygen Analyzer ◽

Gas Purging ◽

Flow Rate Range ◽

Residual Gas

ABSTRACTThe residual impurity gases in the atmospheric rapid thermal processing (RTP) equipment are becoming an important factor in sub-micron ULSI industry. For example, 1% nitrogen in oxygen decreases the RT oxide thickness, and a small amount of moisture or oxygen in nitrogen may strongly affect the RT titanium silicidation. The effective method to reduce the residual gases is to use process gas to purge the chamber. In the present paper the gas purging mechanisms were in-situ investigated in the flow rate range of 10 to 60 slpm using a Quadrapole Residual Gas Analyser (RGA) and gas sensors. The gases for purging studies are N2, O2, He and Ar. It has been found that there are two regimes in the dependence of the residual gas concentration on purging time. Based on the results of systematic experiments, a purging equation, called Pseudo-PST (“perfectly stirred tank) model, has been developed and was used to give the interpretation of the purging process in the atmospheric RTP system. The limitation of the RGA and the oxygen analyzer used to atmospheric RTP system was also discussed.

Download Full-text