A simple parallel conduction extraction method (SPCEM) for MODFETs and undoped GaN-based HEMTs

Abstract

We report a simple method to extract the mobility and sheet carrier densities of conduction channels in conventional modulation doped field-effect transistor (MODFET) structures and unintentionally doped GaN-based high-electron mobility transistor (HEMT) structures for a special case. Extraction of the conduction channels from the magnetic field-dependent data can present number of problems; even the most recent methods encounter great difficulties. For the GaN-based HEMT structures which have lower mobilities and larger effective masses than that of GaAs-based counterparts, these difficulties become more prominent. In this study, we describe a simple method for magnetotransport analysis to extract conduction channels successfully for a special case that is commonly encountered: one bulk channel and one two-dimensional electron gas (2DEG) channel. Advantage of this method is mainly its simplicity. The analysis can be done with only two magnetic field-dependent measurements per temperature step. The method is applied to the magnetotransport results of an unintentionally doped AlGaN/AlN/GaN/AlN heterostructure over a temperature range of 29-350 K and in a magnetic field range of 0-1.5 T (μB<1). The results are then compared with those obtained using a commercial package for these calculations namely: quantitative mobility spectrum analysis (QMSA). © 2008 Elsevier Ltd. All rights reserved

SiC Substrate effects on electron transport in the epitaxial graphene layer

“…[12][13][14][15][16][17][18][19] In order to extract the correct transport parameters of the individual channel in the multilayered structure, such as GaAs/Al x Ga 1-x As and Al x Ga 1-x N/ GaN heterostructures, several extraction techniques were proposed. [12][13][14][15][16]18] Among these techniques, the quantitative mobility spectrum analysis (QMSA) method is the most popular. [14,15] The QMSA technique, which generates optimized quantitative results from the experimental results, can be effectively used for determining the individual carriers in multilayered semiconductors.…”

“…[14,15] On the other hand, a simple parallel conduction extraction method (SPCEM), in order to extract the contributions of bulk and 2DEG carriers in a HEMT or MODFET structure, was proposed by Lisesivdin et al. [18] The mobilities and carrier densities of individual carrier channels in AlGaN/GaN heterostructures [16,18] and GaN bulk layers [19] were investigated successfully by using the SPCEM technique.…”

“…In the SPCEM calculations, some assumptions were made: [18] (1) There are two main contributions to conductivity: 2DEG carrier in graphene layers and a 3DEG bulk carrier in the SiC substrate.…”

“…[9] Since the carriers in different conducting channels do not all have the same drift velocity, single magnetic field Hall measurements can only give an approximate result about the carriers in the multichannel conduction structures. [12][13][14][15][16][17][18][19] To extract the contributions of 2DEG conductivity in graphene layers and the parallel conduction in SiC substrate, the simple parallel conduction extraction method (SPCEM) can be used. [13,15,16] There may be an important parallel conducting channel even for the graphene layers and SiC substrate.…”

The effect of GaN thickness inserted between two AlN layers on the transport properties of a lattice matched AlInN/AlN/GaN/AlN/GaN double channel heterostructure

“…An AlInN/AlN/GaN single channel heterostructure was used as reference. Hall data were first analyzed to extract the temperature dependent mobilities and carrier densities of the bulk and two dimensional (2D) channels using a simple parallel conduction extraction method (SPCEM) [19]. Then, the potential profiles of conduction and valance bands and spatial distribution of the amplitude of the electron wave functions were calculated by solving a 1D nonlinear self-consistent Schrödinger-Poisson equation [20].…”