Emergence of high quality sputtered III-nitride semiconductors and devices

Abstract

This article provides an overview of recent development of sputtering method for high-quality III-nitride semiconductor materials and devices. Being a mature deposition technique widely employed in semiconductor industry, sputtering offers many advantages such as low cost, relatively simple equipment, non-toxic raw materials, low process temperatures, high deposition rates, sharp interfaces, and possibility of deposition on large-size substrates, including amorphous and flexible varieties. This review covers two major research directions: (1) ex situ sputtered AlN buffers to be used for subsequent growth of GaN-based structures by conventional techniques, such as metal-organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), or molecular beam epitaxy (MBE), and (2) deposition of the entire III-nitride layered stacks and device structures by sputtering. Replacing conventional in situ GaN or AlN buffer layers with ex situ sputtered AlN buffers for MOCVD, HVPE, or MBE growth of IIInitride films on sapphire and silicon substrates results in the improved crystal quality through reduction in dislocation density and residual strain. Extensive efforts in the field of sputter deposition of III-nitrides resulted in crystalline quality of sputtered III-nitride films compatible with that of MOCVD and MBE grown layers despite the lower temperatures used in sputtering. For example, sputtering techniques made it possible to achieve GaN layers heavily doped with Si and Ge to electron concentrations in mid-10 20 cm −3 range with mobilities exceeding 100 cm 2 V −1 s −1 , resulting in conductivities as high as those of benchmark transparent conducting oxides such as indium tin oxide (ITO). For moderate levels of doping with Si, mobilities comparable to state-of-the-art MOCVD-grown material have been demonstrated (up to ∼1000 cm 2 V −1 s −1 ). The first promising results have been reported for devices (light emitters and field effect transistors) entirely produced by sputtering.

Low‐to‐Mid Al Content (x = 0–0.56) AlxIn1−xN Layers Deposited on Si(100) by Radio‐Frequency Sputtering

“…[1] In particular, AlInN alloys are special candidates for power electronics, highly efficient emitters, optoelectronic devices, and solar cells. [2][3][4][5][6][7][8] In that sense, radio-frequency (RF) magnetron sputtering allows the deposition of large-area and single-phase AlInN material using this low-cost and low-temperature technology exportable to the industry.…”

“…III‐Nitride semiconductors are interesting materials for the development of novel devices due to their direct bandgap energy tunable from the infrared (0.7 eV) for InN to the UV (6.2 eV) for AlN, their strong chemical and temperature endurance, and their radiation hardness . In particular, AlInN alloys are special candidates for power electronics, highly efficient emitters, optoelectronic devices, and solar cells . In that sense, radio‐frequency (RF) magnetron sputtering allows the deposition of large‐area and single‐phase AlInN material using this low‐cost and low‐temperature technology exportable to the industry.…”

Determination of crystallization conditions of Ge/GaAs heterostructures in scanning LPE method

“…To date, basic methods to fabricate various heterostructures for device applications are metal-organic vapor phase epitaxy, metal organic chemical vapor deposition and molecular beam epitaxy [1][2][3]. Many of these deposition techniques are difficult to apply over a large area and are expensive due to complexity of the apparatus used.…”

High-Selectivity Growth of GaN Nanorod Arrays by Liquid-Target Magnetron Sputter Epitaxy

“…Although many research works on SAG-GaN NRs have been done in the past decade for MBE systems, study on MSE-SAG-GaN NRs is still limited due to the difficulty in handling liquid Ga sputtering source and in developing a proper nanopatterning process [34,35]. Magnetron sputter epitaxy (MSE) is a versatile NR growth technique with multiple distinct advantages, including easy integration on an industrial platform, reproducibility, smaller cost, and the absence of toxic precursors [35,36]. Previous works in a MBE-based system have shown that the effective Ga/N ratio is crucial to achieve high selectivity and high growth rate of SAG nanorods [15].…”