Determination of the laterally homogeneous barrier height of palladium Schottky barrier diodes on n-Ge (1 1 1)

Abstract

a b s t r a c tWe have studied the experimental linear relationship between barrier heights and ideality factors for palladium (Pd) on bulk-grown (1 1 1) Sb-doped n-type germanium (Ge) metal-semiconductor structures with a doping density of about 2.5 Â 10 15 cm À 3 . The Pd Schottky contacts were fabricated by vacuum resistive evaporation. The electrical analysis of the contacts was investigated by means of current-voltage (I-V) and capacitance-voltage (C-V) measurements at a temperature of 296 K. The effective barrier heights from I-V characteristics varied from 0.492 to 0.550 eV, the ideality factor n varied from 1.140 to 1.950, and from reverse bias capacitance-voltage (C À 2 -V) characteristics the barrier height varied from 0.427 to 0.509 eV. The lateral homogenous barrier height value of 0.558 eV for the contacts was obtained from the linear relationship between experimental barrier heights and ideality factors. Furthermore the experimental barrier height distribution obtained from I-V and (C À 2 À V) characteristics were fitted by Gaussian distribution function, and their mean values were found to be 0.529 and 0.463 eV, respectively.

Interface Control Processes for Ni/Ge and Pd/Ge Schottky and Ohmic Contact Fabrication: Part Two

“…Chawanda et al [13] used n-type Ge(111) doped with antimony (Sb) at a density of 2.5 × 10 15 cm −3 . Pd was deposited onto the substrates by vacuum resistive evaporation as explained in Section 2.1.1 of the previous chapter.…”

“…In the first type of samples the surface of the substrates were implanted with Se atoms at an energy of 130 keV Figure 20. Schottky reverse bias C −2 -V characteristics for five Pd/n-Ge samples [13].…”

“…Room temperature forward and reverse bias current-voltage characteristics obtained for five of the Pd/n-Ge contacts[13].…”

“…Room temperature Schottky potential barrier height distribution derived from forward bias I-V characteristics[13].…”

Characteristics of Al/Ge Schottky and ohmic contacts at low temperatures

“…Due to the presence of a potential barrier between metal and semiconductor, a Schottky barrier is created that prevents flow of charge carriers thereby forming a diode with high degree of rectification and faster transitions. Metal/Ge Schottky contacts were widely investigated [1][2][3][4] and barrier height is found to be independent of metal work function due to Fermi level pinning near charge neutrality level [5,6]. Al is a popular choice for making Schottky contacts on Ge and reported to exhibit higher than predicted values of barrier heights and ideality factor [1,[7][8][9].…”