This document defines and describes the electrical, optical, structural, and surface properties of SI GaAs that are considered technically relevant according to the present status of scientific knowledge and material technology.

A specification of the material quality of SI GaAs substrates includes a number of the parameters described below. Depending on the intended application, a particular subset of properties and respective parameters will be considered relevant by the purchaser.

In order to enhance the clarity and applicability of the document, the ordering information in Section 6 subdivides the material parameters in respect of their relative importance, according to general industry perception.

Some material properties and parameters, while intensively discussed in the technical literature, are insufficiently established to allow an unambiguous specification. The available information is nevertheless included to support supplier-purchaser discussions and agreements on these issues.

Each parameter specification requires an agreement about verification. Appropriate information is summarized in Section 5. Available standard test methods elaborated by SEMI, ASTM, and DIN are referenced in Section 3.

A number of the required standard test methods do not exist at present. This document is expected to serve as a guideline and incentive for qualified ASTM, DIN, JEITA, and SEMI committees to develop the missing standard procedures. Conversely, if at present more than one standard test method for verification of a specific parameter exists (see Table 1), a global consensus procedure towards selecting or generating a unique standard is advocated.

The geometrical properties of wafers, in particular orientation, diameter, thickness, flatness and edge rounding, are covered by the series of SEMI M9 specifications and shall not be addressed here.

NOTICE: This standard does not purport to address safety issues, if any, associated with its use. It is the responsibility of the users of this standard to establish appropriate safety and health practices and determine the applicability of regulatory or other limitations prior to use.

Purpose

Substrates with high electrical resistivity and electron drift mobility are needed to fabricate high performance digital and analog microelectronic devices and circuits. Semi-insulating n-type Gallium Arsenide, henceforth termed SI GaAs, has been established worldwide as a preferred substrate material for such applications.

The active layers needed for devices are generated either by ion implantation or by epitaxy. The quality of these layers, and hence the performance, yield and reliability of devices, strongly depends on the bulk and surface quality of the substrate.

This document provides a basis for specifying the material parameters of SI GaAs to support ordering agreements between suppliers and purchasers.