Electrical properties of InP MIS devices

Abstract

Thin film metal-insulator-semiconductor devices have been prepared on n-type InP substrates. The metal used was aluminium and the insulating oxide film was produced using an anodisation technique. Diodes were made with oxide thicknesses of 40 AA and 110 AA and were evaluated using current-voltage measurements over the temperature range 150-350K and also capacitance-voltage techniques. Both sets of measurements were compared with current metal-insulator-semiconductor theory and values were obtained for the barrier height in the semiconductor. Reasonable agreement was found but an anomaly previously observed in the Richardson plot in Al-InP Schottky barriers was again evident in the devices. The capacitance-voltage results indicated a surface-state density in the region of 1012 cm-2 eV-1. Values were also obtained for the barrier height presented to electrons by the insulating layer. This proved to be rather smaller than expected, which suggests that the mechanism of current flow through the layer is not simple tunnelling.

Analysis of inhomogeneous Ge/SiC heterojunction diodes

“…Many solutions were suggested to return linearity to the plots [21][22][23] before the link with inhomogeneities was made 9,11,15,24 . Two techniques exist to modify the classic Richardson plot to extract the barrier height, taking into account SBH lowering due to an inhomogeneous contact.…”

The Cu/n-GaAs schottky barrier diodes prepared by anodization process

“…When the SBDs with a thin interfacial layer (MIS) are considered, it is assumed that the forward-bias current of the device is due to thermionicemission current, and it can be expressed as 11,19,20 (1)…”

“…Thus, the nonideal behavior, caused by the interfacial-layer thickness, may be described by an increase of the n value with increasing oxide thickness. [19][20][21][22][23][24][25] The reverse-bias current does not become independent of the oxide thicknesses, as in Fig. 1.…”

“…It is well known that the presence of an interfacial layer causes the effective barrier height to decrease with increasing bias so that the reverse current does not saturate. [19][20][21][22][23][24][25] Furthermore, as can be seen in Table I, the ideality-factor value for the Cu/n-GaAs SBDs (sample CuG3) with the interfacial layer ranges from 1.32-1.42. The values of n indicate that the device obeys a metal-interface layer-semiconductor (MIS) configuration rather than ideal Schottky diode.…”

“…The values of n indicate that the device obeys a metal-interface layer-semiconductor (MIS) configuration rather than ideal Schottky diode. 11,12,[17][18][19][20][21][22][23][24][25][26] is the laterally homogeneous barrier height. Figure 2 shows high-frequency (HF) C-V characteristics for sample CuG3 at 100 kHz.…”