Recent Progresses in GaN Power Rectifier

Abstract

In this work, both ''Schottky to Schottky'' structure (STS) and pseudo-vertical Schottky barrier diode (pv-SBD) have been processed on GaN heteroepitaxially grown on sapphire or silicon by metal organic chemical vapor deposition (MOCVD) and characterized physically and electrically. Ni and Ti/Al were used to obtain respectively Schottky and Ohmic contacts using rapid thermal annealing (RTA). Adequate passivation steps and insertion of a resistive guard ring were also implemented in pv-SBD. The STS results, presented in this paper, evidence the impact of the substrate on the growth as well as all the progresses that have been done on GaN material quality. Furthermore, we demonstrate that high quality Schottky diodes can be obtained on GaN grown on sapphire by MOCVD. Indeed, ideality factors of 1.09 as well as a barrier height of 1.06 eV were obtained on pv-SBD devices that have a breakdown voltage over 600 V. #

Review of using gallium nitride for ionizing radiation detection

“…The double-Schottky contact structure has three main advantages: 86 (a) The fabrication process is simple in that it requires only one masking step; (b) the structure can be used without any optimized Ohmic contact and is thus usually employed to study and optimize Schottky contacts; and (c) since the thickness of epi-layer is usually less than the range of the a-particles, both electrons and holes contribute to the detection signal and significant trapping of charge carriers is not expected. 10 On the other hand, the structure suffers from several drawbacks: (a) The thin epilayer (<10 lm) results in only partial energy deposition; (b) multiple Gaussian functions are needed to fit the a spectrum; and (c) parasitic capacitance and resistance may exist due to the long distance between the two metal contacts.…”

DLTS analysis of high resistive edge termination technique‐induced defects in GaN‐based Schottky barrier diodes

“…However, the fulfilment of 600 V reverse blocking capability has been demonstrated in Ref. [4]. Besides that, the Schottky contact parameters extracted from the forward I(V) characteristics (see Table 1) indicate an ideality factor close to unity (n ¼ 1) and a higher Schottky barrier closer to …”

“…Resulting from efforts achieved in GaN processing for optoelectronics and RF applications where GaN-based LEDs, lasers [2], and HEM transistors [3] are already commercially available, recent progresses in the growth of thick electronic grade GaN layers have led to a new maturity order that allows considering GaN based power electronics applications. Over the last decade, research activities have targeted GaN process development for power rectifiers and their applications [4]. Due to the lack of high quality freestanding GaN wafers, different structures of Schottky diodes have been evaluated in the literature.…”

“…The achievement of such devices requires plasma RIE etching of GaN, high efficiency Ohmic and Schottky contacts and high performance edge termination structure which includes passivation and guard ring. Process details are given elsewhere [4]. However authors mentioned that, to date, an optimal etching process of GaN with an etch rate of 500 nm min À1 has been performed in our technological platform using an Ar/Cl 2 plasma ICP/RIE etching.…”

Characterization of in-depth cavity distribution after thermal annealing of helium-implanted silicon and gallium nitride

“…Cavities in these materials can be used for different applications, such as gettering of impurities during device processing, smart cut process or the diffusion control of dopants for ultrashalow junctions [1,2,3,4,5]. A further interest of He implantation induced defects in GaN concerns the formation of resistive guard rings in a schottky diode process [6]. Transmission Electron Microscopy (TEM) is an established tool to investigate these structures, but unfortunately it is very time consuming and difficult to determine at a same time a depth distribution profile of the cavities and an observation when defects of few nm to thousands nm are encountered in the same area.…”