Enhanced performance of an AlGaN/GaN high electron mobility transistor on Si by means of improved adatom diffusion length during MOCVD epitaxy

Abstract

Four types of AlGaN/GaN high electron mobility transistor (HEMT) structures have been epitaxially grown on Si substrates by metalorganic chemical vapor deposition (MOCVD) and fabricated into devices. To achieve crack-free device structures, various stress-engineering methods have been employed including the use of AlGaN/AlGaN-graded layers, insertion of low-temperature AlN layers and ion implantation of the AlN/Si substrate. To improve material quality, pulsed MOCVD is used to enhance adatom diffusion length during (Al) GaN epitaxy of various layers in the HEMT structure. A comparison between structural and morphological characteristics of the HEMTs shows improvement in the (0 0 0 2) symmetric rocking curve value to 837.9 s −1 and the surface roughness of 0.21 nm for HEMT structures grown using pulsed epitaxy. An OFF-state breakdown voltage of 217 V at a drain current of 1 mA mm −1 at Vg = −8 V was measured for the structure with enhanced material quality.

Post-annealing effects on pulsed laser deposition-grown GaN thin films

“…Since GaN has high mobility, excellent thermal conductivity, and strong bonding strength, it is widely used in electronic and optoelectronic applications such as blue and UV light-emitting diodes [2,3], semiconductor lasers [4], high electron mobility transistors [5,6], and highpower devices [7,8]. Although high-quality GaN films are usually grown by metal-organic chemical vapor deposition (MOCVD) [9,10] and molecular beam epitaxy (MBE) [11,12], PLD is another preeminent thin film deposition method [13]. The advantage of PLD is as follows [14,15]: first, it can fabricate various films, ranging from metallic to insulating, polymeric or oxides, and even high temperature superconducting materials, as long as the target can be fabricated.…”

Frequency-dependent C-V Characteristic-based Extraction of Interface Trap Density in Normally-off Gate-recessed AlGaN/GaN Heterojunction Field-effect Transistors

“…However, in the case of Schottky-gate HEMTs, there has been remaining problems of large off-state leakage and collapse current which result from a high density of the surface and interface traps [1]. Then the AlGaN/GaN Heterojunction field-effect transistors (HFETs) with the gate-recessed metal-oxide-semiconductor structures were proposed as propitious devices for the normally-off GaN-based HEMT with advantages, such as a thin barrier layer, low gate leakage, and high breakdown voltage [2][3][4].…”

Reverse blocking enhancement of drain field plate in Schottky-drain AlGaN/GaN high-electron mobility transistors

“…Due to high critical breakdown electric field and high two-dimensional electron gas (2DEG) density, AlGaN/GaN high-electron mobility transistors (HEMTs) have been widely investigated as promising candidates for power electronics applications. [1][2][3] Except for the high forward off-state blocking performance and low specific on-resistance (R on ), excellent reverse blocking capability is also desired in a number of applications, such as electric vehicles, class-S amplifiers, and bidirectional switches. [4,5] The drain terminal may be biased at a negative voltage in these applications and this would result in the significant increase of drain current.…”