ISSN:1071-1023    

DOI:10.1116/1.583425

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

The dominant electron trap D‐X center in AlxGa1−xAs has been clearly identified by us to consist of two closely related levels with thermal activation energies of 0.48 and 0.52 eV. Photoionization properties of the two levels have been explicitly measured by us for the first time. A new model for capacitance transients from modulation doped (MD) structures, which takes into account the heterointerface capacitance, is presented to explain the observed anomalous behavior of trap emission in MD structures. Both the thermal and the optical ionization properties of the two D‐X centers in MD structures are measured and discussed.

ISSN:1071-1023    

DOI:10.1116/1.583426

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.583427

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

High‐resolution pulsed laser‐induced photoluminescence (PL) and PL excitation spectroscopy have been carried out in MBE grown GaAs/AlxGa1−xAs multi‐quantum‐well structures at 5 K. At very low laser power levels, fine structures are observed both in the heavy‐hole and the light‐hole excitonic regions. By combining a selective detection method with PL excitation spectroscopy, energy states buried under a broad spectrum can be separated.

ISSN:1071-1023    

DOI:10.1116/1.583428

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.583429

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.583430

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.583431

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

A technique of arsenic‐induced RHEED intensity oscillations has been used to accurately measure arsenic incorporation rates as a function of substrate temperature during the homoepitaxial growths of both GaAs and InAs by molecular beam epitaxy (MBE). Measurements were made at growth temperatures from 350 to 650 °C and at arsenic fluxes of 0.1 to 10.0 monolayer/s. The method measures only the arsenicactuallyincorporatedintothegrowingfilmand does not include the arsenic lost in splitting the arsenic tetramers or lost by evaporation from the sample.

ISSN:1071-1023    

DOI:10.1116/1.583432

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

The application of molecular beam epitaxy (MBE) to the growth of compound semiconductors for devices and monolithic circuits requires excellent film uniformity and reproducibility of growth conditions. Conventional conical crucible cells for group III elements typically provide excellent film uniformity but exhibit a significant flux transient upon shutter opening due to the cooling of the melt surface. Flux transients result in poor control over initial growth stoichiometry and uncertainty over the initial film parameters which limit film reproducibility. This paper reports on a unique pyrolytic boron nitride (PBN) crucible arrangement for group III elements which simultaneously provides excellent film uniformity and a low flux transient. The cell utilizes a deep PBN crucible for a large recessed melt volume and a PBN insert to maintain beam uniformity. The cell provides film thickness and doping variations of less than 2% across a 2‐in.‐diam wafer and a flux transient of less than 3% when the shutter is opened. The usable melt volume is 20 cm3and the operating temperature is approximately 100 °C lower than that of the conical crucible cell. The large cell volume increases run time between cell recharging over conventional conical crucible cells. The melt location deep in the furnace provides long term temperature stability and reduces long term growth rate variations. The high material quality and low oval defect density (<500 cm−2) are comparable to conventional conical cells. The results of the measurement of film parameters are presented and the operation of the cell is described.

ISSN:1071-1023    

DOI:10.1116/1.583374

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

We have constructed a solid arsenic source cracking furnace and have compared the cracking patterns with four different cracking baffle materials: graphite, tantalum, PBN, and molybdenum. The results show that a definite baffle material effect is observed. For graphite, molybdenum, and PBN, greater decomposition is favored at high temperatures, with the PBN baffles being the least effective. For tantalum baffles, an optimal temperature window is obtained and the dimer content drops at temperatures above 850 °C.

ISSN:1071-1023    

DOI:10.1116/1.583375

出版商:American Vacuum Society    

年代:1986

数据来源: AIP