Showing posts with label QCM - Quartz Crystal Microbalance. Show all posts
Showing posts with label QCM - Quartz Crystal Microbalance. Show all posts

Saturday, March 26, 2016

New cyclic azasilanes as volatile and reactive precursors for ALD of SiO2 from Gelest

Here is a very good publication brought to my attention by Henrik Pedersen on Twitter. It is a nice screening exercise of a new class Si precursors for ALD of SiO2 using ozone fom Gelest Inc. SiO2 is one of the most important materials today in the 2nd ALD boom besides silicon nitride. 

As reported earlier here the equipment market for ALD single and multi wafer tools is expected to reach $1.2 billion in the next 2-3 years. One of the reasons behind tremendous growth expectation  is that LPCVD and PECVD just can´t meet the requirements of conformal growth and low thermal budget required by the sub 20 nm Logic and Memory technologies and especially for multi-patterning and also due to the 3D path of 3DNAND. One additional challenge that has to be confronted is to have a stable process that is not affected by surface loading difference due to different chip designs - just imagine the issues with having one specific CVD recipe for each specific litho layer in each specific product in a foundry like TSMC or Globalfoundries.

Here is an excellent publication from Dina Triyoso at Globalfoundries explaining loading effects in the 28nm spacer module PECVD vs ALD SiNx that is free at Research Gate.

The excellent work is form Nicholas Strandwitz research group at the Department of Materials Science and Engineering and Center for Advanced Materials and Nanotechnology, Lehigh University, Bethlehem, USA and has been performed using a the well known workhorse in ALD - the Ultratech/Cambridge Nanotech Savannah S100. This one seems also to be a nice version with a Quartz crystal microbalance (QCM) integrated in the lid from Ultratech.

Cyclic azasilanes as volatile and reactive precursors for atomic layer deposition of silicon dioxide

Ling Ju and Nicholas C. Strandwitz 
J. Mater. Chem. C, 2016, Advance Article, DOI: 10.1039/C5TC03896K

A suite of four volatile aminosilanes, cyclic azasilanes, was used to deposit silicon dioxide (SiO2) films by atomic layer deposition (ALD) over the temperature range 100–300 °C by reaction with O3. The unstable Si–N bonding makes the cyclic azasilanes chemically reactive with hydroxyl surfaces through a ring-opening reaction. Subsequent oxidation with O3 affords silanol groups, which are amenable to further reaction with cyclic azasilanes. The influence of azasilane and O3 exposure times on the growth rate was examined in detail. The growth rates obtained by spectroscopic ellipsometry are 0.6–1.2 Å per cycle for various azasilanes under different ALD conditions, due to side chain structure variation of the precursors. Refractive indices (1.45–1.46) and band gaps (8.5–8.7 eV) are found to be similar to thermal oxide. X-Ray photoelectron spectroscopy (XPS) revealed 3–5 at% C and 0.2–0.4 at% N in the films and an O/Si ratio of ∼1.9 when deposited at 190 °C. The first silane pulse resulted in a surface coverage of ∼1.2 molecules per nm2 as determined by microbalance measurements. The O3 oxidation rate is faster for silanes with Si–OMe groups than those with Si–Me functionalities, and less effective at lower temperatures for some silane precursors. These cyclic azasilanes are promising precursors for ALD SiO2 and surface functionalization, and the variation in the structures provides possibilities to study reaction mechanisms and control surface chemistry.

Wednesday, April 1, 2015

High Temp CNT Modified Colnatec QCM as a GC Detector

The QCM devices and measurement circuit that were used for this study were purchased from Colnatec LLC (Gilbert, AZ). Colnatec’s mass detectors are unique in that the sensors are capable of operation of up to 500 °C without the need of water cooling. Colnatec and others have developed temperature compensation algorithms that improve sensor stability at high temperatures. Also, special QCM discs for high temperature application were obtained from Colnatec LLC (Gilbert, AZ) and were used in this study when explicitly noted.

High Temperature Mass Detection Using a Carbon Nanotube Bilayer Modified Quartz Crystal Microbalance as a GC Detector
Marcel Benz*, Lauren Benz ‡, and Sanjay V. Patel †
† Seacoast Science, Inc., 2151 Las Palmas Drive, Suite C., Carlsbad, California 92011, United States
‡ Department of Chemistry and Biochemistry, University of San Diego, San Diego, California 92110, United States
Anal. Chem., 2015, 87 (5), pp 2779–2787

Abstract Image
A small, portable gas chromatograph (GC) was assembled for the trace detection of controlled substances using a novel quartz crystal microbalance sensor (QCM). The QCM crystal surface was modified with a variety of sorption materials to increase adsorption thereby amplifying mass detection. Single polymer thin film coatings increased the QCM response by 1–2 orders of magnitude, while operating at over 100 °C. Adding a layer of carbonaceous nanomaterial (graphene or carbon nanotubes) above such a film dramatically increased sensitivity by up to 3 orders of magnitude compared to uncoated crystals. Separation and detection of submicrogram quantities of controlled substances was carried out within minutes by employing a GC column and detector temperature ramp up to 220 °C. An additional 10-fold enhancement in sensitivity was achieved by mechanical abrasion of the sample swabs used in the sample introduction process. This study demonstrated a novel use of a polymer composite modified QCM as a chemical sensor at high temperatures


Wednesday, November 12, 2014

Colnatec Unveils All-Inclusive Thin Film Controller

Colnatec is expanding its portfolio of high-precision, thin film measurement and control devices, Colnatec today announced the debut of a compact controller that unites the leading-edge technology of its Eon™ series of PC-based controllers with the modular efficiency of rackmount instrumentation.

Thin Film Controller with Integrated Display
Adaptable. Affordable. Unconventional.

With its integrated display, intuitive user interface, and durable architecture, Eon-ID™ offers a versatile design that adapts easily to a variety of settings - ranging from industrial to laboratory to clean room to research environments - matching or surpassing the capabilities of Inficon™ XTC/3™ and IC6™.

“We’ve identified a growing demand for a stand-alone thin film control solution that incorporates hardware, display, and software into a single enclosure,” said Colnatec CTO Scott Grimshaw. “In answering this demand, Eon-ID™ has exceeded our expectations. Making thin film control more accessible through affordability and efficiency of design, Eon-ID™ has the potential of not only broadening thin film science in general but driving thin film manufacturing opportunities into completely new and unexpected areas of industry.”

Among its numerous features, Eon-ID™ offers the latest Eon Software™ interface, an integrated display allowing for a greater variety of settings and applications, rackmount capability, a temperature compensation system that maintains crystal to within +/- 1°C of preset temperatures, advanced technology that increases reliability and durability in industrial environments.

"Eon-ID™ employs the same temperature-centric technology used in our Eon™ and Eon-LT™ series controllers," noted Colnatec CEO Wendy Jameson. "Eon-ID™ will specifically benefit industries using atomic layer deposition (ALD), optics, OLED, and any other process that requires precision control over very thin layers, especially at temperatures higher than 100°C. Combining precision, simplicity, and cost effectiveness, Eon-ID™ represents nothing less than the state-of-the-art in thin film science."

About Colnatec

Taking a revolutionary approach to thin film design, development, and manufacturing, Colnatec ( manufactures the only commercially available heated quartz crystal microbalances (QCM) for process control of film thickness measurement in high temperature processes such as atomic layer deposition (ALD) or chemical vapor deposition (CVD). Through the use of patented and patent-pending Colnatec technology, researchers, manufacturers, and system-builders have reduced production and run times and costs to improve overall performance - ultimately achieving higher yields and improved process control. Colnatec technology is also frequently used in, encapsulation and high flux deposition of organic light emitting diodes (OLED), optical coatings such as for anti-reflection (PVD), next generation food packaging, and medical device coating, etc. Launched in 2009, Colnatec is the recipient of Department of Energy Phase I and Phase II SBIR awards for high temperature sensors, and one of eight winners of the inaugural Arizona Commerce Authority Innovation Challenge Grant. Colnatec has built a reputation as a bold innovator and a formidable player in a tough, highly competitive marketplace.

Sunday, June 1, 2014

In situ characterization of ALD processes and study of reaction mechanisms for high-k metal oxide formation

"In situ characterization of ALD processes and study of reaction mechanisms for high-k metal oxide formation" is a fresh doctoral thesis to be defended 6th of June 2014 in Helsinki Finland by Mr Yoann Tomczak at University of Helsinki, Faculty of Science, Department of Chemistry, Laboratory of Inorganic Chemistry. To learn more on in-situ studies by QCM and QMS I recommend to read the doctoral thesis by Antti Rahtu that can be downloaded here.
Precursors, processes and materials studied in this thesis.
Yoann Tomczak
University of Helsinki, Faculty of Science, Department of Chemistry, Laboratory of Inorganic Chemistry
Doctoral dissertation (article-based),
Atomic Layer Deposition (ALD) is a thin film deposition method allowing the growth of highly conformal films with atomic level thickness and composition precision. For most of the ALD processes developed, the reaction mechanisms occurring at each step of the deposition remain unclear. Learning more about these reactions would help to control and optimize the existing growth processes and develop new ones more quickly. For that purpose, in situ methods such as quartz crystal microbalance (QCM) and quadrupole mass spectrometer (QMS) are used. These techniques present numerous advantages because they allow monitoring the thin film growth mechanisms directly during the process. Additionally, they do not require separate experiments or large amounts of precursors to test the efficiency of new processes and could be very effective means to monitor industrial processes in real time.

This thesis explores the most common in situ analytical methods used to study ALD processes. A review on the ALD metal precursors possessing ligands with nitrogen bonded to the metal center and their reactivity is provided. The results section reports the reaction mechanisms of ALD processes for the deposition of Nb2O5, Ta2O5, Li2SiO3, TiO2 and ZrO2. All the processes studied are using metal precursors with nitrogen bonded ligands and ozone or water for the deposition of high-k and other oxide films.
This is a Finnish article-based doctoral dissertation, the scientiffic work is mainly reported in the form of published or soon to be published journal articles:
I. “In situ reaction mechanism studies on the new tBuN=M(NEt2)3 -Water and tBuN=M(NEt2)3 - Ozone (M=Nb,Ta) Atomic Layer Deposition processes.” 
Y. Tomczak, K. Knapas, M. Sundberg, M. Ritala, M. Leskelä 
Chem. Mater.(2012), 24(9), 1555-1561 

II. “In situ reaction mechanism studies on atomic layer deposition of AlxSiyOz from Y. Tomczak, K. Knapas, S. Haukka, M. Kemell, M. Heikkilä, M. Ceccato, M. Leskelä, M. Ritalatrimethylaluminium, hexakis ethylaminodisilane and water.”
Chem. Mater.(2012), 24(20), 3859-3867
III. “In situ reaction mechanism studies on lithium hexadimethyldisilazide and ozone atomic layer deposition process for lithium silicate.”
Y. Tomczak, K. Knapas, M. Sundberg, M. Leskelä, M. Ritala
Journal of Physical Chemistry C (2013), 117(27), 14241-14246
IV. “In situ reaction mechanism studies on the Ti(NMe2)2(OiPr)2-D2O and Ti(OiPr)3(NiPr-Me-amd)-D2O Atomic Layer Deposition processes”
Y. Tomczak, K. Knapas, M. Ritala, M. Leskelä
Journal of Vacuum Science and Technology A: Vacuum, Surfaces, and Films (2014), 32(1), 01A121-01A121-7
V. “[Zr(NEtMe)2(guan-NEtMe)2] as a novel ALD precursor: ZrO2 film growth and mechanistic studies”
T. Blanquart, J. Niinistö, N. Aslam, M. Banerjee, Y. Tomczak, M. Gavagnin, V. Longo, E. Puukilainen, H.D. Wanzenböck, W.M.M. Kessels, A. Devi, S. Hoffmann-Eifert, M. Ritala, and M. Leskelä
Chem. Mater.(2013), 25(15), 3088-3095
VI. “Atomic layer deposition, characterization and growth mechanism of high quality TiO2 thin films”
VI. M. Kaipio, T. Blanquart, Y. Tomczak, J. Niinistö, M. Gavagnin, V. Longo, V. Pallem, C. Dussarrat, M. Ritala, M. Leskelä