Automatic Prober for the DC Characterisation of Gallium Arsenide Devices. Part 1. The Measurement Facility

摘要

A computer controlled Auto Prober System has been designed and constructed to allow detailed information to be obtained from the large number of Gallium Arsenide (GaAs) devices fabricated in the Microwave Devices Division (DP2). GaAs substrates up to 2 inch diameter can be processed in the DP2 clean room and typical substrates may contain several thousand devices and test patterns. The prober system consists of two separate facilities, one to carry out the DC measurements and the other to allow the data obtained to be analyzed and correlated. This memo describes the measurement facility and gives details of the DC conditions under which the measurements are carried out. A full description of the software is included in this memo and a listing of the software is given in a separate appendix. The data analysis facility is described in RSRE Memo 4066. Both facilities have been designed as an integrated system and offer a range of on wafer measurements which include characterization of active devices such as GaAs MESFETs (MEtal-Semiconductor Field Effect Transistors) and Schottky diodes as well as measurement routines for use on various test patterns for addressing ohmic contacts and investigating doping profiles of device layers. Passive components such as on wafer capacitors and resistors can be measured.