【摘要】：隨著電子科技的迅速發(fā)展,具有低擊穿電壓、反向漏電流大的傳統(tǒng)肖特基二極管(SBD)已不適用于某些低功耗、大功率的電子市場。由此具有新型結(jié)構(gòu)以及勢壘材料的耐高壓肖特基二極管應(yīng)運而生,該肖特基二極管具有較低的漏電流和正向壓降、耐高壓、高頻特性好以及較強的抗浪涌電流和抗過壓能力。除了適用于高頻整流和開關(guān)電源及保護電路在低壓、大電流場合時作續(xù)流和整流之用,還被廣泛應(yīng)用于高速邏輯電路、通信電源、變頻器和高速計算機中,具有很廣泛的市場前景以及重要的應(yīng)用價值。為了改善肖特基二極管的電學性能,文中采用保護環(huán)和場板終端結(jié)構(gòu),通過改進器件制造工藝過程中勢壘的材料,設(shè)計制備的硅基肖特基二極管耐壓性可達120V。論文中做的主要工作有以下幾方面:(1)系統(tǒng)的闡述了肖特基勢壘二極管的基本工作原理,研究了外延材料的選擇對管芯性能的影響。最終研究表明:在SBD二極管兩端施加一定的反向偏置電壓時,通過穿通模式設(shè)計的外延層可以使管芯的串聯(lián)電阻明顯降低。(2)實驗設(shè)計并制造了尺寸為60mils×60mils的肖特基二極管,其終端結(jié)構(gòu)采用保護環(huán)和金屬場板結(jié)構(gòu)。測試結(jié)果表明:器件反向耐壓值為112V,而傳統(tǒng)肖特基二極管的反向耐壓值一般為45V,此時器件的漏電流僅為2μA;正向電流為3A時,導通壓降為0.71V。(3)改進器件制造工藝過程中形成肖特基勢壘的材料,由具有較大功函數(shù)的NiPt60合金替換傳統(tǒng)的Ni勢壘金屬,通過可靠性實驗測試得出:制備的管芯熱穩(wěn)定性良好,在175℃下工作時具有良好的性能;而對于傳統(tǒng)的鎳勢壘肖特基二極管,最高工作結(jié)溫為125℃。說明肖特基二極管勢壘材料的改變不但改善了管芯的電學特性,而且使其具有較高的可靠性和穩(wěn)定性。(4)為了進一步提高器件的性能,利用Silvaco-TCAD軟件對器件結(jié)構(gòu)參數(shù)及工藝流程進行了仿真分析,并采用改善器件制備工藝的方法:(1)在生長外延前對硅片表面采取相應(yīng)的化學腐蝕措施進行處理;(2)離子注入形成P+保護環(huán)后進行高溫退火推結(jié);(3)采用濺射工藝淀積勢壘金屬并進行高溫合成;(4)金屬反刻后進行PMA退火。試驗結(jié)果表明:采用上述制備工藝可以大幅度減小管芯漏電流,改善了器件反向擊穿特性。
[Abstract]:With the rapid development of electronic technology, traditional Schottky diode (SBD) with low breakdown voltage and high reverse leakage current is not suitable for some low-power and high-power electronic markets. Thus, a novel structure and barrier material with high voltage resistance Schottky diode emerged as the times require. The Schottky diode has lower leakage current and forward voltage drop, high voltage resistance, good high frequency characteristics and strong ability of resisting surge current and overvoltage. In addition to being suitable for high-frequency rectifier and switching power supply and protection circuits for continuous current and rectifier in low-voltage and high-current situations, they are also widely used in high-speed logic circuits, communication power sources, frequency converters and high-speed computers. It has a wide market prospect and important application value. In order to improve the electrical properties of Schottky diodes, the protective ring and the field plate terminal structure are adopted in this paper. By improving the material of the barrier in the fabrication process of the device, the voltage resistance of the silicon Schottky diode is up to 120V. The main work in this paper is as follows: (1) the basic principle of Schottky barrier diode is described systematically, and the influence of epitaxial material selection on the core performance is studied. The final study shows that the series resistance of the core can be significantly reduced by the epitaxial layer designed by the through mode when the reverse bias voltage is applied at both ends of the SBD diode. (2) Schottky diode with the size of 60mils 脳 60mils is designed and fabricated experimentally. Its terminal structure adopts protection ring and metal field plate structure. The test results show that the reverse voltage resistance of the device is 112V, and that of the conventional Schottky diode is 45V. The leakage current of the device is only 2 渭 A. When the forward current is 3A, the on-voltage drop is 0.71V. (3) the material formed Schottky barrier in the process of device fabrication is improved, and the traditional Ni barrier metal is replaced by the NiPt60 alloy with large work function. The results of reliability test show that the prepared core has good thermal stability and good performance at 175 鈩，

本文編號：2373439