Introduction

Abstract

The idea of realizing semiconductor devices in a thin silicon film which is mechanically supported by an insulating substrate has been around for several decades. The first description of the insulated-gate field-effect transistor (IGFET), which later on evolved into the modern silicon metal-oxide-semiconductor field-effect transistor (MOSFET), is found in the historical patent of Lilienfield dating from 1926 [1.1]. This patent depicts a three-terminal device where what is nowadays called the source-to-drain current is controlled by field effect from a gate which is dielectrically insulated from the rest of the device. The piece of semiconductor which constitutes the active part of the device is a thin semiconductor film deposited on an insulator. In a sense, it can thus be said that the first MOSFET was a Semiconductor-on-Insulator (SOI) device. The technology of that time was unfortunately unable to produce a successfully operating Lilienfield device. IGFET technology was then forgotten for a while, completely overshadowed by the enormous success of the bipolar transistor, discovered in 1947 [1.2].