Mobility Enhancement and Breakdown Behavior in InP-Based Heterostructure Field-effect Transistor

Abstract

This study proposes an InAlAsSb/InP heterostructure field-effect transistor ͑HFET͒ grown by a low-pressure metallorganic chemical vapor deposition system. Its InAlAsSb Schottky layer and coupled ␦-doped InP channels cause this HFET to exhibit high two-and three-terminal breakdown voltages. Mobility and two-dimensional electron gas concentration are increased. Additionally, this HFET does not exhibit the frequently observed parallel conduction and bell-shaped characteristics of conventional HFETs. The activation energy is also determined.InP-based heterostructures are extremely attractive for a variety of microwave and optoelectronic applications. 1,2 In particular, InAlAs/InGaAs high-electron mobility transistors ͑HEMTs͒ have exhibited enhanced high-speed and low-noise performance because of their superior electronic transport properties, such as high electron mobilities, high electron velocities, and large ⌫ and L valley energy separation. 3 However, the so-called parallel conduction exists in the high bandgap donor layers of HEMTs. The conducting electrons transfer into high bandgap donor layers under the high current operation, resulting in an additional conducting channel. Because of the low electron mobility in the parallel-channel, the realspace transfer of electrons degrades the device performance. Additionally, the high output conductance and low breakdown voltages of HEMTs limit the use of these devices in high-power microwave applications. Although several approaches have been used to enhance the breakdown in HEMTs, the improvements have been limited. Accordingly, an alternative device technology is required to make further improvements. In 1980, Wood et al. proposed planar doping to improve the doping profile abruptness of Gedoped n-type GaAs grown by molecular-beam epitaxy. 4 The single ␦-doped GaAs field-effect transistor ͑FET͒ has numerous advantages, such as high breakdown voltage and easy control of threshold voltages. 5 Zheng et al. demonstrated the enhanced mobility in coupled ␦-doped layers. 6 However, most work on the ␦-doping technique has been focused on the GaAs and AlGaAs systems. 7-9 An excellent alternative material system is lattice-matched In 0.34 Al 0.66 As 0.85 Sb 0.15 /InP, which has a large bandgap ͑ϳ1.8 eV͒, 10 In 0.34 Al 0.66 As 0.85 Sb 0.15 with a high Schottky barrier ͑ B Ͼ 0.73 eV͒, and a large ⌬E C ͑Ͼ0.7 eV͒ at the InAlAsSb/InP heterojunction. 11-13 InP is an attractive material for use in highfrequency power FETs because it has a high electron peak velocity, a low ionization coefficient, and good thermal conductivity. The coupled ␦-doped InAlAsSb/InP heterostructure field-effect transistors ͑HFETs͒ have been demonstrated to exhibit the high mobility and breakdown characteristics. 14,15 However, the breakdown mechanism and temperature-dependent characteristics of the InAlAsSb/InP HFETs have been neglected. This work proposes an InP-based HFET with coupled ␦-doped InP channels and an In 0.34 Al 0.66 As 0.85 Sb 0.15 Schottky layer. This HFET exhibits high mobility, high two-dim...

Study of the hBN/InP interface by deep level transient and photoluminescence spectroscopies

“…Indium Phosphide (InP) is a promising material for high speed digital, microwave and optoelectronic applications [1,2]. However, one of the limiting factors in the performance and reliability of InP based devices, is the existence of defects introducing deep levels in the energy band gap of the semiconductor.…”

n + -GaAs / p + -InAlGaP / n + -InAlGaP Camel-Gate High-Electron Mobility Transistors

“…The larger conduction-band discontinuity in HEMTs also reduces the output conductance and the real space transfer, improving the performance of the devices. Our previous studies demonstrated the use of alternative InAlAsSb/InP 14,15 and InAlGaP/GaAs 16 materials systems used in microwave devices. Recently, Liu et al presented a series of GaAs/InGaP CAMFETs.…”

“…An effective way to increase the sheet charge density is to use material systems with a large conduction-band discontinuity. [10][11][12][13][14][15] In principle, a larger conductionband discontinuity corresponds to a larger sheet charge density, so the current driving capability is greater. The larger conduction-band discontinuity in HEMTs also reduces the output conductance and the real space transfer, improving the performance of the devices.…”

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

“…InAlAs/InGaAs high electron mobility transistors (HEMTs) on InP substrate have demonstrated excellent high frequency characteristics especially for low noise applications in the microwave and millimeter wave range [1,2]. 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].…”