SEMICONDUCTOR STRAINED LAYERS

During the past 25 years (after the growth of the first pseudomorphic GeSi strained layers on Si) we have seen a steady accumulation of new materials and devices with enhanced performance made possible by strai n. The past year has been good for strained layers. Until recently, sh ort wavelength (violet to green) and mid-infrared (2-5 mu m) regions o f the spectrum were not accessible to photonic devices. Short waveleng th light emitting diodes and laser diodes have been developed using ll l-Nitride and Il-VI strained layers. Improved mid-infrared lasers, usi ng Sb-based Ill-V semiconductor strained layers, have also been fabric ated. These advances have been possible due to improvements in growth techniques as well as in the modelling and computer simulations of lay er compositions and device structures. Full band Monte Carlo simulatio ns of electron transport in strained Si predict very high electron mob ilities. Computer simulations show that complementary metal oxide sili con circuits, fabricated with strained layer GeSi transistors will hav e considerably improved performance. Electronic devices based on GeSi strained layers have shown further improvements in high frequency and high power performance. Many devices based on strained layers are bein g used in commercial equipment. Advances have been made both in modell ing and determining the nonuniform strain, using a Raman technique.