Fabrication and Temperature Dependent Electrical Characterization of Ni/4H-SiC (0001) Schottky Barrier Diodes Equipped with Field Plate and Guard Ring Terminations structure

Gupta, SK and Kumar, V and Pradhan, N and Das, S and Mann, AS and Akhtar, J (2013) Fabrication and Temperature Dependent Electrical Characterization of Ni/4H-SiC (0001) Schottky Barrier Diodes Equipped with Field Plate and Guard Ring Terminations structure. In: International Conference on Diamond and Carbon Materials (DIAM-2013), September 02-05, 2013, Rivadel Garda, Italy. (Submitted)

Microsoft Word (Extended Abstracts) - Submitted Version Download (247Kb)

Abstract

Silicon Carbide (SiC) is an upcoming alternate substrate in the area of diamond and carbon related material research. For many decades in the latter half of the twentieth century, SiC was used in various other sectors, in several applications where unique properties of SiC employed for semiconductor such as inherent radiation-resistance, high operating voltage, high power handing capacity and high temperature operating capacity. Since then, extensive research studies took place to fabricate the active devices based on numerous polytypes of SiC for semiconductor and electronic system. The first commercial use of SiC in semiconductor devices started at the turn off the century. Since then, SiC technology has infiltrated into three major sub-segments of the semiconductor industries; namely the power semiconductor industry, the opto-electronic industry, and the high temperature semiconductor industries. Over the past few years, several research and development (R&D) activities is going on worldwide to develop SiC based device technology that have advanced and sophisticated characteristics and offer better flexibility for use of high power and high temperature applications. 4H-SiC Schottky diodes often show anomalous temperature dependence of device parameters like ideality factor (), Schottky barrier height (SBH), leakage current, series resistance (Rs), turns on voltage etc. Metal-SiC interfaces play very important roles in many high-performance devices application. The fundamental understanding of Schottky barrier formation at these interfaces is therefore of great interest. Current Voltage (I-V) characteristics of Schottky diode based on thermionic emission theory usually reveals an anomalous increase in the barrier height and a decrease in the ideality factor with an increase in temperature. In the present work, the electrical characteristics of Ni/n-type 4H-SiC Schottky diodes in a wide temperature range (25oC to 200oC) were studied. A strong temperature dependence of device parameters obtained from the I–V characteristics was observed and reported in this paper. A 2 diameter 4H-SiC wafers of (0001) orientation with n/n+-type polarity and both sides polished was used in this experiment. In the fabrication of devices, emphasis was focused on not only the influence of the edge termination techniques to improve the device parameters but also the influence of the process adoptability with semiconductor industries for the batch fabrication of Schottky diodes array [1]. A thermally grown oxide field plate edge termination and floating metal (Ni) guard ring was integrated simultaneously in each device structures. A standard optical photolithography process was used to realize the shape and size of discrete parts of devices. To enhance the device parameters vacuum annealing was also carried out at mild temperature [2]. Electrical performance of diced chips was experimentally examined by I-V characterization methods at evaluated temperature. Figure 1 shows the temperature dependent I–V curves of the diode having diameter of 1.2 mm. The characteristic clearly reveals the change in the both forward and reverse bias condition at different temperatures. It can be seen that the forward current increases cautiously with applied voltage, which is governed by thermionic emission effect. The tendency of curve indicates a positive temperature coefficient as a function of temperature. As a result the each individual forward current increases sharply at its turn on voltage as shown in figure 2. It seems that the leakage current at lower bias is governed by thermionic emission where as the reverse current increases with temperature in all cases. On other hand at high reverse bias, the leakage current is less sensitive to the temperature, which is mainly dominated by the tunneling current. The determined experimental values of SBH and  were presented in Figure 3 as a function of the temperature. It has been observed that SBH increases with increasing temperature while the  decreases. It can be seen from Figure 3 that the value of  decreases from 1.70 to 1.16 by increasing the temperature from 25oC to 200oC. The all diode shows an almost ideal behaviour towards higher temperatures. On the other hand, the SBH increases from 0.65 to 1.27 eV by increasing the measurement temperature from 25oC to 200oC, respectively. Figure 3 also shows that the value of decreases from 1.84 to 1.19 and the SBH increases from 0.74 to 1.70 eV by increasing the measurement temperature from 25oC to 200oC, respectively. The series resistance is a very significant parameter of Schottky barrier diodes. A total sum of resistance values, the resistors in series and resistance in semiconductor in the direction of current flow is termed as the resistance of Schottky barrier diodes. In this experiment the series resistance was calculated from the experimental I–V data in forward mode condition of diodes using the method developed by Cheung and Cheung [3]. Figure 4 shows the experimental series resistance values obtained from the semi-log forward bias I–V characteristics as a function of measurement temperature. Rs at room temperature was found to be 4.49, increasing to 17.09 Ω -cm at 200oC.

Item Type:	Conference or Workshop Item (Paper)
Subjects:	Semiconductor Devices > Sensors and Nanotechnology
Divisions:	Semiconductor Devices
Depositing User:	Mr. Jitendra Nath Bajpai
Date Deposited:	27 Jun 2013 09:32
Last Modified:	27 Jun 2013 09:32
URI:	http://ceeri.csircentral.net/id/eprint/221

Available Versions of this Item

• Fabrication and Temperature Dependent Electrical Characterization of Ni/4H-SiC (0001) Schottky Barrier Diodes Equipped with Field Plate and Guard Ring Terminations structure. (deposited 27 Jun 2013 09:32) [Currently Displayed]

Actions (login required)

View Item