離子佈植對雙擴散汲極金氧半場效電晶體之影響

Abstract

隨著半導體製程的發展，將高壓/高功率元件與傳統互補式金氧半場效電晶體的製程技術整合在一起，已成為今日應用市場上最重要的發展。其中雙擴散汲極金氧半場效電晶體是高壓元件中最早被運用的方式，由於其構造簡單，在製程上並不需要加太多的製程條件及光罩數。對於操作電壓在20V以下之元件而言，雙擴散汲極金氧半場效電晶體，仍舊是所有高壓元件中的首選。 在本篇論文中，我們首先藉由模擬的方式去探討離子的植入條件對雙擴散汲極金氧半場效電晶體在電性上的影響，藉此去了解其發生的物理機制，並將由模擬出的結果及趨勢，選擇最適當的條件以改善元件的特性。從過程中，我們發現將植入能量提高，可以提升元件的耐壓能力，並減緩其突然折回的問題，但卻會降低其趨動能力；若提高植入劑量，則可以改善其近似飽合的現象，提高其導通電流及降低關閉漏電流，但其崩潰電壓卻會因此降低。因此，植入劑量及能量便成為改善元件效能上的平衡機制，同時利用高劑量及高能量的條件，將是本篇論文嘗試解決問題的方向。最後成功驗證高植入能量(240KeV)及高植入劑量(1.4×10^13cm-2)的條件可以大幅改善元件的特性，不僅緩和了許多的效應，亦在不影響崩潰電壓太大的情況之下，提升了電流約70%，關閉電流由原來50pA降至約20pA。在此結果之下，尚可縮小元件的尺寸，增加元件密度，並降低導通電阻，對於類似的元件極具競爭力。

With the progress of integrated circuit technology and the trend of system-on-a-chip (SOC), integrating high power devices with low power circuit is an important in the marketing of electronic application. The Double-Diffusion Drain MOS (DDDMOS) is the first device structure proposed to sustain high drain voltage. Although several advanced high voltage devices were developed in the past 20 years, DDDMOS is still the first choice for devices operating at voltage lower than 20 V due to its simple process. In this thesis, we focus on the impact of ion implantation condition on the performance of DDDMOS. Using TCAD simulation tools, it is observed that with the increase of implantation energy, the breakdown voltage increases and the snapback issue is relaxed. However, the driving capability will be degraded due to the formation of non-converted p-type region on the drain surface. If the implant dosage is increased, the quais-saturation phenomenon at high gate voltage, the driving capability, and the turn-off leakage are all improved, but the breakdown voltage would be degraded. These results imply that high dose and high energy might be the better choice. On the basis of TCAD simulation, the implantation energy was raised to 240 KeV and the implantation dose was raised to 1.4×1013cm-2. A 70% increase of saturation current and 75% reduction of turn-off current were obtained. Slightly decrease of breakdown voltage was observed due to the high dose. But the breakdown voltage is still higher than 18V. It is expected that with higher energy and higher dose device performance can be improved furthermore.