Vacuum/volume 4Olnumber 4fpage 337/J 990 0042-207x/90$3.00+.00 Printed in Great Britain G 1990 Pergamon Press plc

Gallium Arsenide Processing-State of the Manufacturing Art

Introduction

In conjunction with the Semiconductor International ‘89 exhi- bition, a technical conference was also held. This special issue contains the proceedings of one of the sessions entitled ‘Gallium Arsenide processing-state of the manufacturing art’. Although the title stated GaAs processing, in reality the materials that were discussed varied over a wide range and included InP based material together with ternary and quaternary semiconductor compounds.

The session consisted of five contributions and the broad aim was to cover the complete cycle from material growth and char- acterization, through the processing and the diagnostics, to the realisation and measuring performance of integrated devices.

The growth and processing of GaAs has matured to the stage where IC production is now realised at the industrial level. Research activities are rapidly moving from the laboratory to product development. One of the main reasons for this is the desirable characteristics of GaAs (and InP) that have specific applications and have now acquired a niche in the semiconductor

market. Possibly the two most important properties are the very high

electron mobility, giving rise to FET’s and the associated family of devices, HEMT’s and HBT’s ; and the direct bandgap, allow- ing the development of optoelectronic devices to be widely

exploited. It is in this latter field, that there exists a large range of appli-

cations in which Si cannot compete. By tailoring the materials GaAs and InP and their associated compounds (GaInAs, GaInAsP, AlInAs and GaAlInAs) to specific compositions, bandgaps can span the range from 0.18 to 2.42 eV for particular applications.

As with all the active semiconductor devices, drive circuits are required, and one method of utilising the well established Si

technology for GaAs IC’s is to incorporate the two material systems. The first paper describes some of the problems en- countered of combining GaAs growth with Si and how these are being overcome.

The second contribution describes some material char- acterization techniques that have been a matter of routine, both for material assessment and also for trouble shooting when devices do not perform as they are required. There are ;I variety of techniques available, depending on the material and ti >, appli- cation. In this paper, besides mentioning the more established methods, such as SIMS, other more recent methods such as GDMS are also covered. The third paper describes some aspects of material processing, so as to be able to configure specific structures for device fabrication and provide some examples in the area of optoelectronics.

It is beneficial to be able to monitor processes in situ to achieve reproducibility and to identify problems immediately, should they occur. The fourth presentation describes diagnostic tech- niques that not only address these issues, but also gives some insight into the chemical and physical mechanisms involved and also demonstrates end point detection in etching through multi- layer structures. The last paper describes the implementation of III-V processing to components and devices and demonstrates the feasibility of optoelectronic integration.

Because of the nature of the meeting, some of the papers contain elements of being a review, but also contain interesting, novel and previously unpublished work.

The authors wish to thank Cahners Exhibitions for permission to publish these proceedings and special thanks to Peter Evison, who organised the conference.

Alan Webb

337