2‐mm‐gate‐periphery GaN high electron mobility transistor s on SiC and Si substrates: A comparative analysis from a small‐signal standpoint

Abstract

In this paper, a comparative analysis has been conducted on GaN high electron mobility transistor (HEMT) technology on Si and SiC substrates. Smallsignal characteristics of 2-mm GaN-on-Si and GaN-on-SiC devices have been investigated. Both devices have the same gate length of 0.5 μm. Special emphasis has been put on the temperature dependence of the buffer/substrate loading effects arising from the Si substrate. As a matter of fact, the "cold" pinch-off admittance (Y-) parameter measurement showed significant loading effect for the Si-based device with respect to the SiC-based one. This has been clearly supported by the analysis of the extracted parameters of the smallsignal equivalent-circuit model. The model was also validated by simulating active scattering (S-) parameters, which showed a very good agreement with the corresponding measurements. The results of this paper highlight the impact of buffer/substrate leakage currents on small-signal characteristics and the importance of taking this into account during the modeling phase of the GaN-on-Si HEMT technology. The lower thermal conductivity of this substrate increases the internal temperature, thus stimulating more leakage and reduction of the device power efficiency.

An efficient extrinsic capacitances extraction method for small‐signal GaN HEMT devices

“…Many approaches have been introduced in the literature to model HEMT GaN extrinsic components from measured S ‐parameters. To address this issue, we have used two main substrate materials, namely, silicon carbide (SiC) and silicon (Si), which are most commonly used 19–21 . The SiC substrate has 390–450 W/m K thermal conductivity and 10 4 to 10 6 Ω‐cm electrical resistivity while the Si substrate has a thermal conductivity 150 W/m·K and an electrical resistivity around 2.3 × 10 5 Ω‐cm 20 …”

“…To address this issue, we have used two main substrate materials, namely, silicon carbide (SiC) and silicon (Si), which are most commonly used. [19][20][21] The SiC substrate has 390-450 W/m K thermal conductivity and 10 4 to 10 6 Ω-cm electrical resistivity while the Si substrate has a thermal conductivity 150 W/mÁK and an electrical resistivity around 2.3 Â 10 5 Ω-cm. 20 Such extrinsic parameters extraction methods can be grouped into two categories: analytical extraction methods and optimization-based methods.…”

Measurement-based Investigation of the DC and RF Transconductance for Various HEMT Technologies in High-and Low-temperature Conditions

“…Many studies have been devoted to the analysis of the temperature effects on the performance of the HEMT devices, focusing on both GaAs [9][10][11][12][13][14][15][16][17][18] and GaN [18][19][20][21][22][23][24][25][26][27][28][29][30][31] semiconductor technologies. The present article is aimed at an experimental investigation of the behavior of various HEMT technologies in highand low-temperature conditions.…”