Material and technological aspects of high-temperature SiC device packages reliability

Abstract

Purpose – The purpose of this paper is to deal with material and technological aspects of SiC diodes assembly in ceramic packages. The usefulness of combinations of different materials and assembly techniques for the creation of inner connection system in the ceramic package, as well as the formation of outer connections able to work at temperatures up to 350°C, were evaluated. Design/methodology/approach – The ceramic package consists of direct bonded copper (DBC) substrate with Cu pads electroplated by Ni or Ni/Au layers on which a SiC diode was assembled by sintering process using Ag microparticles. For the connections inside the ceramic package, the authors used Al/Ni and Au-Au material system based on aluminium or gold wire bonding. The authors sealed the ceramic package with glass encapsulation and achieved a full encapsulation. Outer connections were manufactured using Cu ribbon plated with Ag layer and sintered to DBC by Ag micro particle. The authors investigated the long-term stability of electrical parameters of SiC diodes assembled in ceramic package at temperature 350°C. Findings – The authors have shown that Schottky and PiN SiC diodes assembled with different technologies and materials in ceramic package keep their I-V characteristics unchanged during ageing at 350°C for 400 h. Originality/value – The SiC diodes assembled into ceramic package with Al/Ni or Au-Au inner electrical connection systems and outer connections system based on Ag microparticles sintering process of Cu/Ag ribbon to DBC substrate can work reliably in temperature range up to 350°C.

Cooling Systems of Power Semiconductor Devices—A Review

“…The problem of the effective cooling of electronic devices is a subject of the investigations of packaging constructors [6,7], as well as designers and constructors of electronic circuits containing these devices [8][9][10]. This paper [6] proves that the size of voids in the soldering joint practically has no influence on the efficiency of heat removal from a power semiconductor device.…”

Investigations of mutual thermal coupling between SiC Schottky diodes situated in the common case

“…High temperature packages of SiC Schottky diodes were elaborated at Warsaw University of Technology (Myśliwiec et al, 2015). In a previous paper (Górecki et al, 2016), the authors prove that these packages make it possible to increase the maximum internal temperature of the diode even to 500°C.…”

Examinations of Selected Thermal Properties of Packages of SiC Schottky Diodes

“…The shape of characteristics of two diode chips CB3 and CB4 were not the same before the assembling procedure. It is possible that − due to a defect in the SiC structure − the diode CB3 was more vulnerable to damage during a high-power stress [16]. Another reason for a diode failure may be − inherent in the package − inefficient heat removal from the device structure.…”

“…The detailed information about the construction of the tested diodes is published in [16]. The measured current-voltage characteristics of the diodes CB3 and CB4 are presented in Fig.…”

“…Warsaw University of Technology undertook examinations that led to a construction of a package for SiC Schottky diodes that would be resistant to high temperatures [16]. The measurements of thermal properties: the thermal resistance and the transient thermal impedance of packaged SiC Schottky diodes have been recently performed at Gdynia Maritime University.…”