MBE Components from Veeco Enabling Innovative Materials Research and Cost Effective Device Production

Topic List

Background
Sources
Crucible Types
Industry Changing Valved Crackers
Specialty Sources and Gas Crackers
Leading Sources for Production MBE
Expanded Source Options
Software and Electronics
Veeco, Consistently Producing Industry Changing Firsts

Background

Since our inception in 1986, Veeco has been and continues to be the world’s leading supplier of MBE components, thanks in part to our material-specific sources—the first to suit the evaporation characteristics of a certain group of elements or compounds. We commercialized solid source and gas cracking sources to thermally decompose (crack) large molecules into simpler species. Our uniquely designed valved crackers not only crack molecules but also modulate flux with a patented valve mechanism. This innovation made MBE a viable production technology. Our latest innovations are enabling the development and production of advanced nitride- and oxide-based devices.

Figure 1. Family of Veeco Components

Sources

Veeco offers the most comprehensive selection of sources, including single and dual filament designs. These designs are offered in high and low temperature models in capacities from 1cc to 1700cc. Veeco’s SUMO® sources, dual filament in design, utilize uniquely designed and patented crucible shapes. This means only Veeco can deliver the largest charge capacity without sacrificing material quality or source performance. Comprised of a cylindrical reservoir with a small tapered orifice, the SUMO source delivers excellent flux stability, fewer defects, large charge capacity, and minimized shutter transients. In addition, Veeco also offers varying traditional and emerging application-specific source solutions, including oxides and nitrides.

Crucible Types

The type of crucible required for a source is dictated by the material, application and MBE system. Different sizes are available and each source is optimized for use with a specific crucible. Crucibles are usually constructed of PBN but other materials are also available. The SUMO crucible features a unique orifice with a small aperture that provides excellent flux uniformity, long term flux stability and a large charge capacity.

Table 1. Crucibles

SUMO Crucible

Straight Wall Crucible

Conical Crucible

Uniformity

Excellent

Decreases as charge is depleted

Excellent

Charge Capacity

Excellent—capacities up to 1700cc

up to 700cc

up to 700cc

Long-Term Flux Stability

Excellent

Good

Poor

Shutter Transients

Low

High

High

Orientation

Upward, downward without using an insert

Upward

Upward

Typical Use

Dopant, small, medium and large charge capacity

Dopant, small and medium charge capacity

Dopant, small charge capacity

Material Type

PBN, Ta, Graphite, Quartz

PBN, Ta, Graphite, Alumina, W, BeO, ZrO2, Quartz

PBN, Ta, Graphite, Alumina, W, BeO, Quartz

Industry Changing Valved Crackers

Veeco valved crackers mechanically control flux density via a valve mechanism, making it possible to accurately and reproducibly modulate the beam equivalent pressure. In the past decade, we’ve installed more than 700 Veeco valved crackers, including the world’s most versatile and reliable units for arsenic and phosphorus. In addition, Veeco offers valved crackers for selenium, sulfur, antimony, tellurium, magnesium, zinc, cadmium-tellurium, and cadmium along with a valved source for mercury. These sources provide the best quality material, offer longer uptimes, and come in the largest selection of sizes. Furthermore, the new Veeco SMC-II Series Automated Valve Positioner ensures precise and repeatable operation of all Veeco valved sources.

Our newest valved source, the Mark V Valved Cracker for Arsenic incorporates an innovative nozzle design, through Veeco’s flux modeling capability. This design dramatically reduces material consumption by a factor of four compared to previous valved sources yet maintains excellent flux uniformity.

Specialty Sources and Gas Crackers

On-going developments in materials technology require specialty sources with capabilities beyond radiative heating. Veeco provides the solutions. Our UNI-Bulb® is a leak-free RF plasma source for activating stable source gases such as nitrogen and oxygen. It greatly increases GaN growth rates and offers excellent stability and reproducibility. Customized high uniformity (typically ~2%) aperture plates are available for most commercial MBE systems. An accompanying Autotuner increases the source’s efficiency and ease of use. The Atom-H gas cracker provides catalytic cracking of the H2 source gas directly at the hot filament. Other sources include CBr4 for carbon doping and NH3 for nitride applications, both of which utilize Veeco’s nozzle technology to achieve excellent uniformity and utilization.

Leading Sources for Production MBE

Our SUMO sources and valved sources have the highest capacity and the best reliability for production MBE systems. The patented crucible in our SUMO sources improves your run times while maintaining excellent uniformity. Out valved crackers allow almost instantaneous flux changes. Arsenic need not be reloaded during every system vent since the valve may be closed to protect the charge from oxidation. The ability to load additional arsenic before the charge is fully depleted from the crucible also improves uptime. These sources continue to be used on >80% of production systems in the field, due to their lowest cost of ownership advantage.

Expanded Source Options

As researchers explore more materials from the periodic table, Veeco provides more source options. Our patented negative draft PBN technology enables the only proven antimony valved cracker. Veeco offers a variety of new oxygen-resistant and ammonia-resistant components that can operate at high temperatures and required partial pressures for emerging oxide and nitride applications.

Software and Electronics

Our newest release ECS1 Molly® Software (for Equipment Control System 1) is designed to enable new instrumentation (specifically, the Wago “sidecar” modular I/O platforms) with better performance and greater configurability than the previous data acquisition cards. This allows users to utilize a wider range of in-situ monitoring and control capabilities. This latest version release includes: EpiTrend “always-on” data recorder; “Liberator” off-line EpiTrend data viewer and export utility; support for new operational modes of MBE instrumentation (cross-over/specialized temp controllers and slaving of source power supplies); and extensive scripting language improvements (user-defined functions for process specific functionality and user-written communications protocols for unsupported instrumentation).

The newly released Veeco SMC-II Series Automated Valve Positioner provides control of all Veeco Valved Sources. The unit provides remote (computer), local (keypad) or manual (hand-operated) control of the fluxes generated, as well as remote control of the valve position via the unit remote interface. This ensures repeatable operation using optically encoded position feedback.

The Veeco DC Power Supplies produce optimal temperature control resolution. They map source dependent voltage range requirements to full PID output range, and provide constant power output even as load characteristics change.

Veeco, Consistently Producing Industry Changing Firsts

Table 2. Veeco innovations and user benefits

Veeco Innovations

User Benefit

SUMO Sources

Improves uniformity, increases capacity and uptime

Dual Filament

Reduces oval defects, providing higher device yields

Low Temperature Sources

Provides excellent temperature stability with high vapor pressure materials

High Temperature Sources

Deposits magnetic materials and other low vapor pressure materials

Oxygen Resistant Components

Provides long lifetime for high oxygen partial pressure environments

Ammonia Resistant Components

Provides long lifetime for high ammonia partial pressure environments

Valved Crackers for Arsenic and Phosphorus

Thermally cracks large molecular species and mechanically controls material flux

Corrosive Series Valved Crackers

 Enables growth of extremely complex device structures containing

antimony, tellurium, magnesium, cadmium, cadmium-tellurium

UNI-Bulb RF Plasma Sources with Autotuner

Provides reactive molecular species for nitrogen, hydrogen and oxygen applications

Atom-H Sources

Provides thermally cracked atomic hydrogen

Low Temperature Gas Injectors

Supports growth with ammonia , CBr4 and other low temperature gases

Hydride Injectors

Provides efficient thermal cracking of arsine and phosphine

High Temperature Substrate Heaters

Enables high temperature growth for GaN and oxide applications

Nozzle Technology

Improves uniformity and utilization for a wide variety of sources

Source: Veeco
For more information on this source please visit Veeco.

Date Added: May 1, 2008 | Updated: Jun 11, 2013
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