K Bohlin

Deep-level transient spectroscopy measurements using high Schottky barriers

Abstract This paper describes a method to investigate minority-carrier traps in semiconductors by utilizing high Schottky barrier diodes in DLTS (deep-level transient spectroscopy) measurements. This offers an advantage compared to using pn diodes in that no excessive heat treatment which can alter the semiconductor deep-level properties has to be performed. One of the best-known deep-level systems is the gold levels in silicon. The method is demonstrated for the gold donor level in n -type silicon by using iridium as Schottky contact.

Complementary Si MESFET concept using silicon-on-sapphire technology

Complementary Si MESFETs (CMES) for integrated circuits using silicon-on-sapphire are described. Not only the gate, but also the source and drain of the n-transistors and p-transistors are Schottky junctions, using very high barrier heights for the gate and low barrier heights for source and drain. Only two Schottky metals are used: one, Ir or Pt, giving a high barrier on nSi, and hence low on pSi; the other, Er or Tb, showing the opposite behavior. The basic differences between MES and MOS are pointed out and design criteria for CMES inverters using normally-off type transistors are given.<<ETX>>

Schottky rectifiers on silicon using high barriers

Abstract Schottky diodes are presently used for power rectification because of their low forward voltage drop. However, they have only been fabricated on relatively low resistivity and thin semiconductor layers. Hence the reverse breakdown voltages are low. To make diodes that stand higher reverse voltages, low doped material of sufficient thickness is necessary. Ordinary Schottky barriers do not inject minority carriers and the resistive voltage drop at high forward currents will be large, However, for high Schottky barriers ∼ 0.9eV, minority carriers are injected and the series resistance is decreased. In this paper we report results from one-dimensional numerical calculations as well as experimental results of high barrier Schottky diodes. We discuss the voltage drop at high forward currents for different substrate resistivity and thickness, as well as values of the high barrier.

Computer modeling and comparison of different rectifier (M-S, M-S-M, p-n-n + ) diodes

A computer method is used to investigate the forward characteristics of high-barrier Schottky diodes with different back contacts. A discussion of rectifier-parameter optimization is presented, together with comparisons of different diode types, including p-n-n+diodes. The superiority, in certain voltage ranges, of the high-barrier Schottky diodes over p-n-n+diodes is demonstrated.

A p-channel MESFET on silicon using an erbium gate

Abstract A p -channel MESFET (metal semiconductor field-effect transistor) has been fabricated using erbium as gate material and iridium as source and drain contacts. The results show that it is possible to achieve p -type devices with characteristics comparable to n -type devices. As substrate silicon on sapphire (SOS) was used since it gives a well-defined channel thickness. The thickness of the silicon was 0.6 μm; after processing this was reduced to about 0.5 μm, which was, thus, the ultimate channel thickness.