In Situ Wafer Cleaning Prior to Selective HemiSpherical Grain (HSG) Poly-Silicon Deposition Using RT-CVD

1998 ◽  
Vol 525 ◽  
Author(s):  
B. J. Brosilow ◽  
S. Levy ◽  
Y. E. Gilboa
Keyword(s):  
Silicon Surfaces ◽  
Ex Situ ◽  
Native Oxide ◽  
Poly Silicon ◽  
Wafer Cleaning ◽  
Cleaning Procedures ◽  
Temperature Window ◽  
Oxide Removal ◽  
Cell Capacitance

ABSTRACTHemispherical grained (HSG) polycrystalline-silicon surfaces are used in DRAM manufacturing to enhance cell capacitance by increasing the surface area of the capacitor electrodes. We study the formation of HSG poly-silicon in a Rapid Thermal CVD (RT-CVD) cluster tool with in-situ native oxide removal. Compared to conventional ex-situ wet cleaning procedures, use of the in-situ native oxide removal both decreases the process temperature at which HSG formation occurs and increases the width of the temperature window within which desirable HSG layers are formed.

Polysilicon Emitter Transistors Manufactured using a Novel Limited Reaction Processing System

1989 ◽  
Vol 146 ◽  
Author(s):  
Fred Ruddell ◽  
Colin Parkes ◽  
B Mervyn Armstrong ◽  
Harold S Gamble
Keyword(s):  
Thermal Processing ◽  
Rapid Thermal Processing ◽  
Processing System ◽  
Bipolar Transistors ◽  
Native Oxide ◽  
Plasma Oxidation ◽  
Oxide Removal ◽  
Polysilicon Emitter ◽  
Reaction Processing

ABSTRACTThis paper describes a LPCVD reactor which was developed for multiple sequential in-situ processing. The system is capable of rapid thermal processing in the presence of plasma stimulation and has been used for native oxide removal, plasma oxidation and silicon deposition. Polysilicon layers produced by the system are incorporated into N-P-N polysilicon emitter bipolar transistors. These devices fabricated using a sequential in-situ plasma clean-polysilicon deposition schedule exhibited uniform gains limited to that of long single crystal emitters. Devices with either plasma grown or native oxide layers below the polysilicon exhibited much higher gains. The suitability of the system for sequential and limited reaction processing has been established.

In Situ Spectroscopic Ellipsometry Study of the Oxide Etching and Surface Damaging Processes on Silicon Under Hydrogen Plasma

1999 ◽  
Vol 591 ◽  
Author(s):  
I.M. Vargas ◽  
J.Y. Manso ◽  
J.R. Guzmán ◽  
B.R. Weiner ◽  
G. Morell
Keyword(s):  
Spectroscopic Ellipsometry ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Surface Damage ◽  
Silicon Surfaces ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Si Substrates ◽  
Oxide Etching

ABSTRACTWe employed in situ ellipsometry in the monitoring of surface damage to monocrystalline silicon (Si) substrates under hydrogen plasma conditions. These measurements were complemented with spectroscopic ellipsometry and Raman spectroscopy, in order to characterize the surface conditions. It was found that heating the Si substrate to 700°C in the presence of molecular hydrogen produces etching of the native oxide layer, which is typically 10 Å thick. When the already hot and bare silicon surface is submitted to hydrogen plasma, it deteriorates very fast, becoming rough and full of voids. Modeling of the spectroscopic ellipsometry data was used to obtain a quantitative physical picture of the surface damage, in terms of roughness layer t ickness and void fraction. The results indicate that by the time a thin film starts to grow on these silicon surfaces, like in the chemical vapor deposition of diamond, the roughness produced by the hydrogen plasma has already determined to a large extent the rough nature of the film to be grown.

Cleaning of Silicon Surfaces for Nanotechnology

2008 ◽  
Vol 573-574 ◽  
pp. 77-117 ◽  
Author(s):  
Oliver Senftleben ◽  
Hermann Baumgärtner ◽  
Ignaz Eisele
Keyword(s):  
Surface Roughness ◽  
High Mobility ◽  
Crystal Defects ◽  
Silicon Surfaces ◽  
Ex Situ ◽  
Chemical Cleaning ◽  
Gas Atmosphere ◽  
Wet Chemical ◽  
Device Properties

An overview of various cleaning procedures for silicon surfaces is presented. Because in-situ cleaning becomes more and more important for nanotechnology the paper concentrates on physical and dry chemical techniques. As standard ex-situ wet chemical cleaning has a significant impact on surface quality und thus device properties, its influence on further processes is also considered. Oxygen and carbon are unavoidable contaminations after wet chemical treatment and therefore we discuss their in-situ removal as one of the main goals of modern silicon substrate cleaning. As surface roughness strongly influences the electrical quality of interfaces for epitaxy and dielectric growth, we concentrate on techniques, which meet this requirement. It will be shown that multi-step thermal sequences in combination with simultaneous passivation of the clean surface are necessary in order to avoid recontamination. This can be achieved not only for ultra hich vacuum but also for inert gas atmosphere. In this case the process gases have to be extremely purified and the residual partial pressure of contaminats such as oxygen and carbon has to be negligible. It will be demonstrated that 800°C is an upper limit for thermal treatment of silicon surfaces in the presence of carbon because at this temperature SiC formation in combination with a high mobility of silicon monomers leads to surface roughness. In addition mechanical stress causes dislocations and crystal defects.

Thermally Driven In-Situ Removal of Native Oxide Using Anhydrous Hydrogen Fluoride

1993 ◽  
Vol 318 ◽  
Author(s):  
Pushkar P. Apte ◽  
Heungsoo Park ◽  
Krishna C. Saraswat ◽  
C. R. Helms
Keyword(s):  
Hydrogen Fluoride ◽  
Native Oxide ◽  
Epitaxial Silicon ◽  
Crystal Silicon ◽  
Silicon Deposition ◽  
Native Oxides ◽  
Anhydrous Hydrogen Fluoride ◽  
Thermally Driven ◽  
Oxide Removal

ABSTRACTIn-situ native-oxide removal is critical for epitaxial single-crystal silicon deposition, for polysilicon emitters and contacts and for ultrathin gate dielectric films in integrated circuit (IC) fabrication. We have developed an in-situ, thermally-driven, anhydrous hydrogen fluoride (AHF)-based native-oxide removal technique in which the wafer is treated by AHF at low temperatures (300-400°C) and a short (10 sec) 950°C ‘spike’ in AHF-H2 immediately prior to Si deposition. This process removes native oxides formed by standard wet cleans such as HC1:H202 and NH4OH:H202, as well as native oxides formed by the clean-room ambient. Further, the technique is an effective pre-clean for both polysilicon and epitaxial silicon deposition. This flexibility, combined with other salient features such as simplicity and a low thermal budget, make the process eminently suited for IC fabrication.

A Complementary Wafer Cleaning and Growth Process for Low Temperature, Defect Free, Selective Silicon Epitaxy

1992 ◽  
Vol 259 ◽  
Author(s):  
Jon T. Fitch ◽  
Dean J. Denning
Keyword(s):  
Steady State ◽  
Low Temperature ◽  
Growth Process ◽  
Process Integration ◽  
Native Oxide ◽  
Growth Processes ◽  
Silicon Epitaxy ◽  
Wafer Cleaning ◽  
Cvd Growth ◽  
Oxide Removal

ABSTRACTLow temperature (<850°C) defect free selective silicon epitaxy has been achieved with a conventional barrel type reactor (base pressure -10−4 Torr) using complementary cleaning and growth processes: a wet multi-step oxidizing clean, and a novel non-steady state CVD growth process. With this combination of cleaning and growth processes, it is shown that the need for a high temperature (950-1000°C) insitu native oxide removal step, which may be incompatible with advanced VLSI process integration, is eliminated.

Thin oxides with in situ native oxide removal [n-MOSFETs]

1997 ◽  
Vol 18 (9) ◽  
pp. 417-419 ◽  
Author(s):  
A. Chin ◽  
W.J. Chen ◽  
T. Chang ◽  
R.H. Kao ◽  
B.C. Lin ◽  
...  
Keyword(s):  
Native Oxide ◽  
Oxide Removal

Light Scattering Measurement Of Surface Topography During Formation Of Titanium Silicide.

1995 ◽  
Vol 406 ◽  
Author(s):  
C. Lavoie ◽  
C. Cabral ◽  
L. A. Clevenger ◽  
J. M. E. Harper ◽  
J. Jordan-Sweet ◽  
...  
Keyword(s):  
Light Scattering ◽  
Surface Topography ◽  
Titanium Silicide ◽  
Ex Situ ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Elastic Light Scattering ◽  
Poly Silicon ◽  
Light Scattering Measurement

AbstractThe evolution of the surface topography during the phase transformations of titanium silicide has been studied using elastic light scattering at two different collection angles. The light scattering measurements were performed simultaneously with x-ray diffraction and resistance measurements for titanium films deposited on either Si(100) or on poly-silicon substrates. At selected points during annealing, the samples were cooled rapidly to room temperature and analyzed ex situ using Nomarski microscopy. We find that, depending on the detection geometry, the in situ light scattering shows preferentially the formation of the C49 or C54 TiSi2 phase as well as differentiates between inversion and agglomeration on poly-silicon substrates.

Development of Remote Plasma Enhanced Ohemical Vapor Deposition Processes Through the use of in Vacuo Electron Diffraction and Electron Spectroscopy

1989 ◽  
Vol 165 ◽  
Author(s):  
R. A. Rulder ◽  
G. G. Fountain ◽  
S. V. Hattangady ◽  
J. B. Posthill ◽  
R. J. Markunas
Keyword(s):  
Electron Diffraction ◽  
Vapor Deposition ◽  
Electron Spectroscopy ◽  
Process Integration ◽  
Chemical Vapor ◽  
Ex Situ ◽  
Remote Plasma ◽  
Wafer Cleaning ◽  
Cleaning Procedures ◽  
Deposition Processes

AbstractRemote plasma enhancecd chemical vapor deposition techniques have been developed for a wide variety of processes. These include SiO2, Si3N4, Si, Ge, GaN, GaAs, and a-Si:H depositions. This development has been enabled through the use of electron diffraction and electron spectroscopy techniques. These techniques have been used to qualify cleaning procedures prior to epitaxial or dielectric depositions. They have beeii used to qualify epitaxial deposition conditions by defining suitable.temperature and rate conditions. And, they have been used to evaluate cross-contamination issues. In situ techniques have been used in conjunction with ex situ characterizations to identify and correct problems in wafer cleaning, epitaxy, and process integration.

Gadolinium Oxide Gate Dielectrics for GaN MOSFETs

2001 ◽  
Vol 680 ◽  
Author(s):  
B.P. Gila ◽  
J.W. Johnson ◽  
K. N. Lee ◽  
V. Krishnamoorthy ◽  
S. Bates ◽  
...  
Keyword(s):  
Single Crystal ◽  
Oxide Films ◽  
Gadolinium Oxide ◽  
Ex Situ ◽  
Native Oxide ◽  
Breakdown Field ◽  
Thermally Stable ◽  
Amorphous Films ◽  
Substrate Temperatures

ABSTRACTSubstrate preparation of GaN, both in-situ and ex-situ, and the growth of gadolinium oxide, Gd2O3, by Gas source molecular beam epitaxy (GSMBE) have been investigated. Ex-situ cleaning techniques included wet chemical etching and UV-ozone treatments to remove surface contaminants and the native oxide. In-situ cleaning consisted of thermal treatment with and without exposure to an electron cyclotron resonance (ECR) oxygen plasma. A GaN (1x3) streaky RHEED pattern was the final product of this surface treatment study. Various growth initiation techniques were explored to produce Gd2O3 films with different microstructures as evidenced by RHEED, TEM, and XRD. Gd2O3 films planarized the initial GaN surface and stoichiometry was maintained over a range of substrate temperatures (300° to 650°C). Single crystal gadolinium oxide films were grown at substrate temperatures of 600-650°C. These films exhibited a breakdown field strength (EBD) of ∼1MV/cm, and showed high leakage current at high forward bias due to defects within the oxide. Single crystal oxide films were found to be thermally stable at annealing temperatures up to 1000°C. Quasi-amorphous films were grown at a substrate temperature of 100°C. These films exhibited a higher E BD of ∼3MV/cm and an interface state density of 3 × 1011 cm−2eV−1. However, the quasi-amorphous films were not thermally stable at 1000°C, showing evidence of re-crystallization in x-ray diffraction (XRD) scans.

Microanalysis of Tungsten Silicide/Polysilicon Interface: Effectiveness of in Situ Rie Clean on Removal of Native Oxide

1990 ◽  
Vol 182 ◽  
Author(s):  
Ronald S. Nowicki ◽  
Patrice Geraghty ◽  
David W. Harris ◽  
Gayle Lux
Keyword(s):  
Oxide Layer ◽  
Silicon Surface ◽  
Secondary Ion Mass Spectrometry ◽  
Film Deposition ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Tungsten Silicide ◽  
High Temperature Heat Treatment ◽  
Oxide Removal

AbstractThe presence of a thin (10-30Å) oxide (“native oxide”) layer on a silicon surface prior to the deposition of another film on that surface can contribute todifficulties with subsequent device processing steps, e.g. contact metallization and hightemperature annealing or oxidation. Thus, the in situ process capability of “native oxide” removal affords an advantage over the conventional method of aqueous hydrofluoric acid cleaning prior to a film deposition step. This study describes such a technique, in which an in situ pre-deposition clean with C2F6 gas, using reactive ion etching (RIE) prior to tungsten silicide deposition, is employed. This technique allows post-silicide deposition high-temperature heat treatment and wet oxidation without loss of film adhesion or other obvious degradative effects. We also report the useof Secondary Ion Mass Spectrometry (SIMS) to show that this procedure has een effective in the removal of the oxide layer prior to silicide deposition. This study includes definition of the RIE etch parameters which provide acceptable etch selectivity of the oxideto silicon, and avoidance of excessive fluoropolymer formation on the silicon surface.

Sign in / Sign up

Export Citation Format

Share Document