TITLE: "Assessment of Bulk Gallium Arsenide"

SPEAKER: Professor Sebahattin Tüzemen,

TIME: Thursday Jan. 18, 2001 at 4 PM

PLACE: George P. Williams, Jr. Lecture Hall, (Olin 101)

Since GaAs material was introduced for Metal Semiconductor Field Effect Transistor (MESFET) and opto-electronic device technology, it has become more important than ever to produce good quality substrates. However in as-grown and annealed materials, it has been observed that there always exists precipitates (such as that of As), dislocations and point defects (such as EL2, Reverse-Contrast, carbon and zinc) that affect the optical and electrical characteristics of GaAs. Therefore, quantity as well as the uniformity of these defects always matters in whether a substrate is suitable for device manufacturing. Different growth and subsequent annealing processes result in different defect and uniformity configurations. This makes the assessment of material produced by certain growth processes and subsequent heat treatments rather crucial. In this seminar, the basis of some characterization techniques to evaluate GaAs will be emphasized and some typical experimental results will be discussed.