Impact of Gate–Drain Spacing on Low-Frequency Noise Performance of <italic>In Situ</italic> SiN Passivated InAlGaN/GaN MIS-HEMTs

Abstract

In this paper we investigated the gate-drain access region spacing (L GD) effect on electrical and noise performance of InAlGaN/GaN metalinsulator-semiconductor high electron mobility transistors (MIS-HEMTs) using in situ SiN cap layer as gate insulator. Different L GD of InAlGaN/GaN MIS-HEMTs using sub-10 nm barrier layer are studied. Low-frequency noise measurements have been carried out for the first time in order to analyze the impact of the gate-drain spacing on the electrical characteristics. The noise of the channel under the gate has been identified as the dominant channel noise source for L GD < 10 μm. Finally, the calculated Hooge parameter (α H) is equal to 3.1 × 10 −4. It reflects the high material quality while using sub-10 nm InAlGaN layer, which is promising for high-frequency applications. Index Terms-Channel resistance, gate-drain spacing, in situ sin passivation, InAlGaN/GaN, low-frequency noise (LFN), metal-insulator-semiconductor high electron mobility transistor (MIS-HEMT). I. INTRODUCTION G AN-based high electron mobility transistors (HEMTs) have demonstrated their potential for telecommunication and power applications owing to the high electrical breakdown field (3.3 MV/cm) and the high electron mobility (2 ×10 3 cm 2 • V −1 • s −1) of GaN material [1]. Extensive research and technology development enabled GaN-based HEMTs to significantly improve over the last two decades.

Impact of the in situ SiN Thickness on Low-Frequency Noise in MOVPE InAlGaN/GaN HEMTs

“…Similar dependence over V GS -V TH indicating the dominant channel noise is located under the gate, as reported in previous works [25,26]. In [27], the channel noise under the gate was also the main contribution of the total channel noise for for low gate-drain access region spacing L GD < 10 µm.…”

“…In agreement with these results, it can be pointed out that the current collapse level within these devices as assessed by pulsed measurements has been found to be similar regardless of the SiN cap layer thickness. We previously analyzed S ID /I D 2 dependence over the gatedrain spacing of InAlGaN/GaN MIS-HEMTs by considering two noise sources in the channel: channel noise under the gate and channel noise in the gate-drain access regions [27].…”

“…Here, the source and drain contact resistances and the gatesource access region resistance are negligible, hence the noise sources of these resistances are not considered in the model. Following the procedure of [27] -3 with no significant impact of L GD . Similar dependence over V GS -V TH indicating the dominant channel noise is located under the gate, as reported in previous works [25,26].…”

Low-Frequency Noise Behavior of AlGaN/GaN HEMTs with Different Al Compositions

“…Low-frequency noise (LFN) measurement for AlGaN/GaN HEMTs is an efficient tool to exam device performance, analyze material defects, and study device reliability [5][6][7][8]. Many research groups have reported by investigating the effects of in situ/ex situ passivation layers [9,10], the gate-to-drain distance [7], and the types of GaN buffer layer [11] on the LFN of AlGaN/GaN HEMTs.…”

“…Low-frequency noise (LFN) measurement for AlGaN/GaN HEMTs is an efficient tool to exam device performance, analyze material defects, and study device reliability [5][6][7][8]. Many research groups have reported by investigating the effects of in situ/ex situ passivation layers [9,10], the gate-to-drain distance [7], and the types of GaN buffer layer [11] on the LFN of AlGaN/GaN HEMTs. M. D. Hasan, et al [6] demonstrated that the AlGaN/GaN metal-oxide-semiconductor (MOS)-HEMT with Al composition of 20% exhibited a lower noise level than that of the device with Al composition of 35%.…”