On the temperature-dependent characteristics of metamorphic heterostructure field-effect transistors with different Schottky gate metals

Abstract

Comprehensive and systematical comparisons of temperature-dependent characteristics of In 0.42 Al 0.58 As/In 0.46 Ga 0.54 As metamorphic heterostructure field-effect transistors (MHFETs) with various Schottky gate alloys are studied and demonstrated. The influence of the Schottky barrier height on the impact ionization effect and its associated device performance are also investigated. Better dc and microwave characteristics can be obtained by using the higher metal work function of gate alloys, e.g., Ti/Au, Ni/Au and Pt/Au. In particular, the device with a Pt/Au gate alloy shows the superior device performance in breakdown voltage, threshold voltage, maximum transconductance, output conductance, voltage gain and microwave properties at room temperature. Furthermore, the device with a Ti/Au gate alloy shows the thermally stable performance in threshold voltage, maximum transconductance, output conductance and voltage gain over a wide operating temperature range (from 300 to 510 K). Consequently, the studied devices with appropriate Schottky gate contacts provide the promise for high-speed and high-temperature electronic applications.

Effect of the non-annealed ohmic-recess approach on temperature-dependent properties of a metamorphic high electron mobility transistor

“…Overall, the degradation of the studied devices manifests itself in the reduction of I DS , g m,max and the increase of R s and R d . Owing to the use of the NAOR approach, the studied device A shows lower degradation rates in I DS and g m,max at the temperatures of 400, 430 and 460 K. In addition, due to the thermal stability of the Ti/Au gate alloy [16], the studied devices show lower degradation rates in I DS and g m,max at the temperatures of 400, 430 and 460 K. This implies that the refractory metal of Ti is effective in preventing the Au metal diffusing into the active structure and eliminating the leakage current [11,17].…”

Thermal-stability performance of a metamorphic high electron mobility transistor (MHEMT) with non-annealed Ohmic contacts

“…On the other hand, to acquire such high performance devices on cheaper and less brittle GaAs substrates, the metamorphic buffer layers have been widely used [3,4]. In addition to high performance and affordable manufacturing cost, long term reliability is a key requirement of microelectronic devices for system applications.…”