Production of GaAs and InP Based Heterostructures
- PDF / 414,006 Bytes
- 8 Pages / 420.48 x 639 pts Page_size
- 113 Downloads / 214 Views
PRODUCTION OF GaAs AND InP BASED HETEROSTRUCTURES H. JOrgensen, R. K. Schreiner, M. Deschler AIXTRON GmbH, J(licher Strape 336-338, 5100 Aachen, FRG ABSTRACT The complete requested range of epitaxial deposition from one monolayer to tens of microns is available integrating LP-MOVPE and LP-VPE into wafer fabrication. Uniformity across 2 inch wafers for thickness, composition, and show a variation of less than 2 %. Electrical properties of the 1014 doping cm 3 range and less for background doping, carrier mobilities of 210,000 cm 2/Vs for AIGaAs and 190,000 cm 2/Vs for GalnAs, both HEMT structures, are achieved. FWHM of 3.4 meV and 18.6 meV for 10 nm and 2 nm GaInAsP wells have been measured. GaAsP layers including a "graded" layer reveal FWHM of 15 nm. A new model for the understanding of high growth rates in the hydride system is demonstrated. INTRODUCTION Semiconductor device technology has impressively advanced during the past decade. Therefore the demand has dramatically increased for semiconductor material of excellent crystal quality and extremely sharp lattice-matched heterojunctions for the application in optoelectronic and ultra high speed devices as e. g. QW Laser, HEMT, and MISFET. Additionally large volume fabrications of high-efficiency components like low-current and printer LED as well as solar cells and photocathodes are of tremendous interest. Different thin film deposition techniques for III-V semiconductors like LPE, VPE, MOVPE, and MBE have been investigated to provide the necessary control of epitaxial layer composition and thickness. Low pressure metal organic vapor phase epitaxy (LP-MOVPE) has proven its ability to produce e. g. double heterojunctions of required quality for devices integrated into light wave communication technique /1/. Vapor phase epitaxy (VPE) at atmospheric pressure impressed by delivering films for GalnAs PIN diodes /2/3/ JEFTs /4/, and relatively thick GaAsP structures for visible LEDs /5/ on large production scale. However, uniformity, especially for the VPE process was not completely satisfying. First approaches of improvement /6/ applying low pressure were encouraging with the disadvantage of drastically reduced growth rate. The present paper will demonstrate latest film properties depending on the vapor phase epitaxial systems (VPE - MOVPE) as well as on the composition, such as AIGaAs, GaAsP, GalnAs, and GalnAsP. Fundamentals of the reaction mechanism, responsible for extraordinary high growth rates in the hydride system, will be discussed in detail. EXPERIMENTAL Both vapor phase epitaxial systems include a gas flow controlling and supply system offering switching times of less than a second. Constant low pressure conditions, e. g. of 20 mbar are accomplished by a rotary pump together with a control valve. As sources for group V elements AsH 3 and PH 3 of 100 %, each are used. Layers have been deposited on GaAs and InP 2 inch wafers of (100)direction with a misorientation of approx. 2 degrees to the (110) direction. In LP - MOVPE the cold wall horizontal reactor is
Data Loading...
