Frederick Hochberg

Effect of low temperature annealing on the surface conductivity of Si in the Si-SiO 2 -AI system

Studies on insulated-gate field effect devices fabricated on both n- and p-type Si have shown the existence of inversion layers on p-type surfaces and of accumulation layers on n-type surfaces. The degree of inversion or accumulation was characterized by measuring the total series capacity of the SiO2 gate and the underlying Si as a function of an applied dc potential. The initial surface conductivity, as measured by the source to drain conductance g8d at zero gate bias, indicates that most of the surface charge is immobile. Prolonged heat treatments at 350°C on p-type substrates have resulted in a two order-of-magnitude increase in g8d accompanied by little or no change in the total surface charge density Nt. On n-type substrates, however, the same treatment results in a factor of 5 decrease in Nt. The effects of these treatments on the surface uniformity as well as on appropriate device parameters are reported.

A thin-film integrated incandescent display

Incandescent alphanumeric displays using a 16-bar format are obtainable today. They employ 1 mil incandescent tungsten helices strung between support posts. This paper describes a new incandescent display device, fabricated by microelectronic thin film techniques. Such techniques allow high resolution dot-matrix displays to be produced, with all the cost advantages obtained from the employment of modern L.S.I. thin-film processing.