1278619 九、發明說明： 【發明所屬之技術領域】 本發明是有關於一種感測器（sensor)，特別是指一種 氣體感測器及其製作方法。 疋曰 【先前技術】 半導體氣體感測器是用以偵測一氧化碳（c〇)、甲烷 (㈤等各種氣體的存在之感測器。除了家用漏氣藝報器： 外二也應用至其他領域的各種機器，例如：空氣清淨機、 換氣扇、空調的換氣監視器、微波爐的烹調控制、酒精檢 測等。此外，由於氣體感測器應詩搭配有偵測廢氣侵入 車内的警報系統，及偵測環保廢氣（例如：N0x)等設施的需 求量亦日益提高，因此，氣體感測器在市場的需求量亦備 受矚目。 半導體氣體感測器的構造簡單，一般常見的Taguchi 型感測器（Taguchi-type sensor)，是在管狀絕緣體（例如 :氧化銘）的内壁面上形成二氧化錫（Sn〇2)、二氧化鈦 (Ti〇2)、氧化辞（ZnO)或氧化鐵（以.）等的金屬氧化物 (metal oxide)燒結體（sintered material)以作為一氣體 感測層’並於如述的金屬氧化物燒結體的兩端安裝電極後 ’進一步地利用δ又置於该管狀絕緣體内的加熱線圈（heater coil)對該Taguchi型感測器進行加熱至約3〇(rc的操作溫 度，藉以偵測氣體附著於該金屬氧化物燒結體表面所產生 的電阻值（resistance)變化。 參閱附件一，、是以Sn〇2-x層作為一氣體感測層說明該氣 1278619 體感測層與電阻值的變化關係。在沒有脫氧氣體 (deoxidizing gas)存在的狀態下（亦即，SnOh層吸附氣體 前），大量空氣中的氧會捕捉電子並附著於晶體（crystal) 表面’晶體表面的施體電子（donor electrons)被轉移至吸 附的氧粒子上’致使在空間電荷層（Space charge layer) 中留下正電荷’以在晶界（grain boundary)間處形成一表 面能障（surface potential)作為對抗電子流動（electr〇n flow)的位能能障（barrier)，並呈現出電阻值高、電流不 易流通的狀態。相對地，參閱附件二，若脫氧氣體存在時（ 亦即’ Sn〇2層吸附氣體後），則氧負電荷的表面密度減少， 且位於晶界處的能障高度降低，因此自由電子的量增加且 電阻值降低。 此外，亦可藉由網版印刷（screen printing)法將一主 要由二氧化錫所構成的氣體感測膠（paste)塗佈於一元件基 材上並予以燒結，藉以構成一封裝型（packaged type)氣體 感幻器用的氣體感測層。然而，此封裝型氣體感測器之其 ，構件，例如•·加熱器、金導線、引腳（pin)、活性碳過濾 為（charcoal filter)及遮罩等構件之製作過程為此技術領 域，所熟知’因此，在此不再多加詳述。此封裝型氣體感 測=的操作條件是與前述的Taguchi型氣體感測器相同， 亦而利用加熱器對該氣體感測層予以升溫達約3⑽。C的操作 溫度才可實施。 、 另外，為因應半導體製程（semic〇nduct〇r process)的 技術需求，元件亦傾向輕薄短小化。因此，參閱圖卜 12786191278619 IX. Description of the Invention: [Technical Field] The present invention relates to a sensor, and more particularly to a gas sensor and a method of fabricating the same.疋曰[Prior Art] The semiconductor gas sensor is a sensor for detecting the presence of various gases such as carbon monoxide (c〇) and methane ((5). In addition to the household gas leakage urinal: the second is also applied to other fields. Various machines, such as: air purifiers, ventilation fans, ventilation monitors for air conditioners, cooking controls for microwave ovens, alcohol detection, etc. In addition, because gas sensors should be matched with an alarm system that detects the intrusion of exhaust gases into the vehicle, and The demand for facilities such as environmentally friendly waste gas (eg N0x) is also increasing. Therefore, the demand for gas sensors in the market is also attracting attention. The structure of semiconductor gas sensors is simple, and the commonly used Taguchi type sensors (Taguchi-type sensor), which forms tin dioxide (Sn〇2), titanium dioxide (Ti〇2), oxidized (ZnO) or iron oxide (by .) on the inner wall surface of a tubular insulator (for example, Oxide). A metal oxide sintered body is used as a gas sensing layer' and after electrodes are mounted on both ends of the metal oxide sintered body as described, 'further utilizing δ The heater coil placed in the tubular insulator heats the Taguchi type sensor to an operating temperature of about 3 Torr (the rc is used to detect the resistance value of the gas attached to the surface of the sintered metal oxide body) (resistance) change. Refer to Annex I, which shows the relationship between the sensing layer of the gas 1278619 and the resistance value by using the Sn〇2-x layer as a gas sensing layer. In the state where no deoxidizing gas exists. Underneath (that is, before the SnOh layer adsorbs gas), a large amount of oxygen in the air captures electrons and adheres to the crystal surface. The donor electrons on the crystal surface are transferred to the adsorbed oxygen particles. A positive charge is left in the space charge layer to form a surface potential between the grain boundaries as a potential energy barrier against electron flow (electr〇n flow) ), and exhibits a state in which the resistance value is high and the current is not easily circulated. Relatively, referring to Annex 2, if deoxidizing gas is present (that is, after the Snn 2 layer adsorbs gas), the oxygen is negative. The surface density of the charge is reduced, and the height of the energy barrier at the grain boundary is lowered, so the amount of free electrons is increased and the resistance value is lowered. In addition, a screen printing method can be used mainly by tin dioxide. A gas sensing paste is applied to a component substrate and sintered to form a gas sensing layer for a packaged type gas sensor. However, the manufacturing process of components of the packaged gas sensor, such as a heater, a gold wire, a pin, a charcoal filter, and a mask, is a technical field. It is well known 'and therefore will not be described in detail here. The operating condition of the package type gas sensing = is the same as that of the aforementioned Taguchi type gas sensor, and the gas sensing layer is heated by the heater to about 3 (10). The operating temperature of C can only be implemented. In addition, in order to meet the technical requirements of the semiconductor process (semic〇nduct〇r process), components tend to be lighter and shorter. Therefore, see Figure Bu 1278619
Philip C.H. Chan、Gui-zhen Yan、Lie-yi Sheng、 Rajnish L Sharma 及 Zhenan Tang 等人於 Micro Electro Mechanical Systems, The 14th IEEE International Conference, 21-25 Jan (2001) pp. 543-546·揭露一種利 用表面微機械（surface micro-machining)的積體氣體感測 器 l(integrated gas sensor)技術。 該積體氣體感測器1，包含：一矽基材11、一形成於 該石夕基材11上的熱氧化矽（thermal Si〇2)層12、一形成於 該熱氧化矽層12上的氮化矽（Si3N4)層13、複數形成於該氮 化石夕層13上的多晶矽（poly—Si)加熱塊μ、一覆蓋該等加 熱塊14的氧化矽層15、複數形成在該氧化矽層15上的加 熱電極16、複數用以分別内連接（inter該等加熱 塊14及該等加熱電極16的導電插塞17(piug)、一形成於 該氧化石夕層15上的Sn〇2氣體感測層18、複數形成於該氣體 感測層18上的接觸電極層19及一夾置於該熱氧化矽層12 及該氮化矽層13之間的氣體閘道i〇(air gate)。 首先’在該熱氧化矽12層上形成一作為犧牲層 (sacrificial layer)用的多晶矽層，並依序地於製作後續 的該氮化矽層13、該等加熱塊14及該氧化矽層15等各層 元件之後’進一步地形成複數分別貫穿該氮化矽層13及該 氧化石夕層15的餘刻孔1 h〇ies)並利用餘刻劑 (etching agent)移除該犧牲用的多晶矽層，藉以構成該氣 體問iL 10並致使該氣體感測層Μ被懸置（s⑽的nde(j)於 该矽基材11的上方。此外，利用濺鍍（sputtering)法在該 1278619 氧化矽層15上形成一金屬錫薄膜’並進一步地對該金屬錫 薄膜施予一溫度介於300。〇至35〇t的熱退火（thennal annealing)藉以製得該氣體感測層18。其中，位於該氣體 閘道ίο内的空氣之熱傳係數（thermal c〇nductivity)低， 因此，藉由該氣體閘道10可使得由該等加熱塊14產生的 熱能集中於該氣體感測層18並防止被傳遞至該矽基材u。 前面所提及的數種氣體感測器製程繁複，此外，不論 疋兀*件的製程溫度亦或是元件的操作溫度皆需高於3〇〇£>c。 因此，在元件製作過程中，對於在積體電路（integrated circuit)中由鋁（A1)所構成的傳輸線路之元件製作而言較 為不利。再者，元件於操作過程中，由於需將元件升溫至 3〇〇C的操作’凰度，熱響應時間（resp〇nse以啦）及氣體響 應時間略長，因此，消耗功率（p〇wer c〇nsumpt i〇n)高亦降 低實用性。 由上所述，如何簡化氣體感測器的製程並降低氣體感 測器的操作溫度，以減少消耗功率高、響應時間過長等問 題，並增加氣體感測器在積體電路整合的實用性，是目前 開發氣體感測器相關領域者所需解決的一大難題。 【發明内容】 〈發明概要〉 别述習知技術中所提及的氣體感測層（例如：％〇2層）於 才木作時而升溫的原因在於，由前揭習知等製程所製得的 Sn〇2層之能隙（energy band肋幻高達3·5 α至4 〇…之 門因此’需由外部提供加熱源（heating source)使SnCh 1278619 層的載子遷移率（carrier mobility)具備足夠的能量，致· 使Sn〇2層在吸附氣體分子時可形成電阻的變化。 由前所述，本發明是利用溶膠凝膠（s〇1—gel)法於一帶 有載子（carriers)且引導連接有兩接觸電極的半導體材料 · 上形成一氣體感測層。參閱附件三，是以一氧化碳、Sn〇2層 及f有P型載子的半導體層說明本發明之氣體感測器的運 作原理。當Sn〇2層吸附一氧化碳氣體分子時，藉由蕭特基-現象（schottky effect)的影響造成一氧化碳氣體分子與 · Sn〇2層介面間（interface;亦即附件三中的介面丨）的能障# 下降，間接地導致該帶有p型載子的半導體層之能障下彎 因而使得該帶有p型載子的半導體層之載子遷移率下降並 產生電阻上升的現象。由前所述，由於介面丨處的能障下 降，因此，可推得本發明使用溶膠凝膠法所製得的氣體感 測層之能障，是低於揭示在習知技術所製得的氣體感測層 ，因此，在室溫下具有對氣體（例如：一氧化碳）進行吸附 與釋放的能力。 因此，本發明之目的，即在提供一種氣體感測器。 · 本發明之另一目的，即在提供一種氣體感測器的製作 ' 方法。 於是’本發明之氣體感測器，包含··一基材、一電阻 結構、至少二連接該電阻結構的接觸電極（c〇ntact electrode)，及一覆蓋該電阻結構且由溶膠凝膠法（s〇i — gel process)所製得的氣體感測層（gas Sens〇r layer)。 該基材具有一第一表面及一相反於該第一表面的第二 9 1278619 表面。 且由一具有 包含下列步 該電阻結構是形成於該基材之第二表面 複數載子（Gangers)的半導體材料所製成。 另外，本發明之氣體感測器的製作方法， (a) (b) 提供一基材； 具有複數载子的半導體材料所 於該基材提供一由一 製成的電阻結構； (c)形成至少二連接該電阻結構的接觸電極；及 ⑷以溶膝凝膠法提供—氣體感測層以覆蓋該電阻結構 〃本發明的功效在於，可簡化氣體感測器的製程並降低 氣體感測器的操作溫度’藉以減少消耗功率高、響應時間 過長等問題，並增加氣體感測器在積體電路整合的實用性 〈發明詳細說明〉 本發明之氣體感測器，包含：一基材 '一電阻結構、 ’ 一連接5亥電阻結構的接觸電極，及一覆蓋該電阻結構 且由溶膠凝膠法所製得的氣體感測層。 该基材具有一第一表面及一相反於該第一表面的第二 表面。 β亥電阻結構是形成於該基材之第二表面’且由一目有 複數載子的半導體材料所製成。 較佳地，該氣體感測層是由一選自於下列所構成之群 10 1278619 組的材料所製成：二氧化錫（Sn〇2)、三氧化二鐵、氧 化辞（ZnO)、二氧化鈦（Ti〇2)及氧化鎢（w〇3)。在一具體實施 例中’該氣體感測層是由二氧化錫所製成。 較佳地，該電阻結構是—形成在該基材之第二表面上 的電阻層’且該電a層是由該具有複數載子的半導體材料 所製成。更佳地’該具有複數載子的半導體材料是—p型 半導體材料或1型半導體材料其中—者。適用於本發明 之該p料導體材料可以是_ p型多㉔（pQly_SiR— p 型多晶鍺（Ge) ’且適用於本發明之該η型半導體材料可以 是- η型多晶矽或- η型多晶鍺。在一具體實施例中 型半導體材料是一 ρ型多晶石夕。 " 較佳地，該電阻層具有一預定圖案。更佳地，該預定 圖案是由一呈一正弦方波的條狀體所構成。 值得-提的是，本發明亦可以是湘擴散（diffusi〇n) 或離子佈植（ion implantatiQn)等方式，於該基材的第二 表面處形成-具有ρ型載子或n型載子其中一者的擴散： 亦或是井層(well layer)，藉以構成該由具有複數載子： 半導體材料所製成的電阻結構。 此外，參閱圖2，本發明之氣體感測器的製作方法，勹 含下列步驟： ^ (a) 提供一基材； (b) 於該基材提供一由一具有複數載子的半導體材 所製成的電阻結構； 厂 (c) 形成至少二連接該電阻結構的接觸電極；及 11 1278619 (d)以溶膠凝膠法提供一氣體感測層以覆蓋該電卩且乡士 構。 較佳地，該步驟（d)的氣體感測層是由下列步驟所構成 (A) 提供一四氯化錫（SnCl4)水溶液； (B) 提供一選自於不列所構成之群組的驗性· (alkalinity)水溶液：氫氧化銨（NH4〇H)及甲醯胺 _ (HCONH2); (C) 混合該四氯化錫水溶液及該鹼性水溶液以製備得· 一前驅物（precursor); (D) 將該前驅物塗佈（coating)於該電阻結構上；及 (E) 對塗佈有該釗驅物的基材施予升溫以製得一由二 氧化錫所構成的氣體感測層。 較佳地’該步驟（b)是利用鍍膜及微影 (photol i thography )製程於該基材之一上表面上形成一具 有一預定圖案的電阻層以構成該電阻結構，且該電阻結構 是由該具有複數載子的半導體材料所製成。其中，該具有_ 複數載子的半導體材料及形成於該電阻層的預定圖案等說 明已分別揭示於前，因此，在此不再多加詳述。 值得一提的是，本發明之氣體感測器亦適合應用於由· 標準互補式金氧半導體(c〇IDplementary meta卜 seimconductor，·簡稱CM〇s)製程所構成的積體整合電路 (IC )板上。 【實施方式】 12 1278619 、有關本發明之前述及其他技術内容、特點與功效，在 以下配合參考圖式之'一個具體實施例的詳細說明中，將可 清楚的呈現。 〈具體實施例〉 參閱圖3,本發明氣體感測器的一具體實施例，包含·· -基材2、-電阻結構3、至少二連接該電限結構3的接觸 電極4，及-覆蓋該電阻結構3且由溶膠凝膠法所製得的氣 體感測層5。 該基材2具有—第一表面21及一相反於該第一表面21 的第二表面22。 參閲圖4 ’說明未形成有該氣體感測層5的電阻結構3 。該電阻結構3是-形成於該基材2之第二表面22上的電 阻層3卜該電阻層31是且由—p型多晶梦所製成，並具有 一由正弦方波之條狀體所構成的預定圖案。 以下配合參_ 3及圖4 ,說明該具體實施例之製作方 法。 首先，利用例如化學氣相沉積法（_之鐘膜製程及微 影製程，在該基材2的第二表φ 22上（意即；上表面上）形 成-由正弦方波之條狀體所構成的預定圖案之ρ型多晶矽 層’藉以完成該電阻層31並定義出該電阻結構3。進一牛 地’於該電阻層31的兩側形成該等接觸電極4，藉以由^ 界對該等電極4提供一電性連接。 接續地’冑10 g的四氯化錫溶於200 ml的去離子水 OH water)以調配得一四氯化錫水溶液，另外，混合該四 13 1278619 氯化錫水溶液與5 m 1且濃度為3 6 %的氫氧化銨水溶液以製 備得一含有錫及氧的前驅物。最後，將該含有錫及氧的前 驅物塗佈且覆蓋於該電阻層31上並施予i〇〇°c持溫2小時 的熱處理’猎以構成該氣體感測層5並完成氣體感測的 製作方法。以下簡單地說明該具體實施例之氣體感測層的 化學反應式：Philip CH Chan, Gui-zhen Yan, Lie-yi Sheng, Rajnish L Sharma, and Zhenan Tang et al., Micro Electro Mechanical Systems, The 14th IEEE International Conference, 21-25 Jan (2001) pp. 543-546. Surface micro-machining integrated gas sensor technology. The integrated gas sensor 1 includes a tantalum substrate 11 , a thermal iridium oxide layer 12 formed on the zea substrate 11 , and a thermal yttrium oxide layer 12 formed thereon. a yttrium nitride (Si3N4) layer 13, a polycrystalline silicon (poly-Si) heating block μ formed on the nitriding layer 13, a yttrium oxide layer 15 covering the heating blocks 14, and a plurality of yttrium oxide layers formed thereon The heating electrode 16 on the layer 15 and the plurality of conductive plugs 17 connected to the heating block 14 and the heating electrodes 16 and the Sn 〇 2 formed on the oxidized layer 15 a gas sensing layer 18, a plurality of contact electrode layers 19 formed on the gas sensing layer 18, and a gas gate sandwiched between the thermal yttria layer 12 and the tantalum nitride layer 13 First, a polycrystalline germanium layer for a sacrificial layer is formed on the 12 layers of the thermal yttrium oxide layer, and the subsequent tantalum nitride layer 13, the heating block 14 and the yttrium oxide layer are sequentially formed. After each layer of the layer 15 and the like, 'further forming a plurality of residual holes 1 h penetrating through the tantalum nitride layer 13 and the oxidized stone layer 15 respectively And removing the polycrystalline germanium layer for sacrificial by an etching agent, thereby constituting the gas iL 10 and causing the gas sensing layer to be suspended (n(j) of the s(10) Further, a metal tin film is formed on the 1278619 yttria layer 15 by sputtering method, and the metal tin film is further subjected to a temperature of 300 〇 to 35 〇t. The gas sensing layer 18 is obtained by a thermal annealing method in which the thermal c〇nductivity of the air located in the gas gate ίο is low, and therefore, the gas gate 10 can be made The heat energy generated by the heating blocks 14 is concentrated on the gas sensing layer 18 and prevented from being transferred to the crucible substrate u. The several gas sensor processes mentioned above are complicated and, besides, The process temperature or the operating temperature of the component must be higher than 3 & > 。. Therefore, in the component fabrication process, for the transmission line composed of aluminum (A1) in the integrated circuit Component production is more disadvantageous. During the process, the power consumption (p〇wer c〇nsumpt i〇) is required because the temperature of the component is raised to 3 〇〇C, the radiance, the thermal response time (resp〇nse), and the gas response time are slightly longer. n) high also reduces the practicality. From the above, how to simplify the process of the gas sensor and reduce the operating temperature of the gas sensor to reduce the problem of high power consumption, long response time, and increase the gas sensor The practicality of integrated circuit integration is a major problem that needs to be solved in the development of gas sensor related fields. SUMMARY OF THE INVENTION <Summary of the Invention> The reason why the gas sensing layer (for example, the layer of % 〇 2) mentioned in the prior art is heated at the time of the wood production is that it is manufactured by the prior art process. The energy gap of the Sn〇2 layer (energy band ribs up to 3·5 α to 4 〇...the door therefore needs to provide a heating source from the outside to make the carrier mobility of the SnCh 1278619 layer. Having sufficient energy to cause the Sn 〇 2 layer to form a change in electrical resistance when adsorbing gas molecules. As described above, the present invention utilizes a sol gel (s〇1 - gel) method for a carrier (carriers) And a gas sensing layer is formed on the semiconductor material to which the two contact electrodes are connected. Referring to the third embodiment, the gas sensor of the present invention is described by a carbon monoxide, a Sn2 layer and a semiconductor layer having a P-type carrier. The operation principle. When the Sn 〇 2 layer adsorbs carbon monoxide gas molecules, the interface between the carbon monoxide gas molecules and the Sn 2 layer is caused by the influence of the Schottky effect (interface; that is, the interface in Annex III).丨)'s energy barrier #降,间This causes the barrier of the semiconductor layer with the p-type carrier to be bent down, thereby causing the carrier mobility of the semiconductor layer with the p-type carrier to decrease and the resistance to rise. As described above, due to the interface 丨The energy barrier at the place is reduced. Therefore, it can be inferred that the energy barrier of the gas sensing layer prepared by the sol-gel method of the present invention is lower than the gas sensing layer which is disclosed in the prior art, and therefore, The ability to adsorb and release a gas (e.g., carbon monoxide) at room temperature. Accordingly, it is an object of the present invention to provide a gas sensor. Another object of the present invention is to provide a gas sensor The method of the present invention. The gas sensor of the present invention comprises: a substrate, a resistor structure, at least two contact electrodes connected to the resistor structure, and a cover structure a gas sensing layer (gas Sens〇r layer) prepared by a sol gel process. The substrate has a first surface and a second surface opposite to the first surface 9 1278619 And one has The resistor structure is made of a semiconductor material formed on a second surface of the substrate by a plurality of carriers (Gangers). In addition, the method for fabricating the gas sensor of the present invention, (a) (b) provides a a substrate; a semiconductor material having a plurality of carriers; the substrate is provided with a resistive structure made of one; (c) forming at least two contact electrodes connected to the resistive structure; and (4) providing a gas by a knee-solving method The sensing layer covers the resistive structure. The present invention has the advantages of simplifying the process of the gas sensor and reducing the operating temperature of the gas sensor, thereby reducing problems such as high power consumption, long response time, and increased gas sensation. The utility of the detector in the integrated circuit integration <Description of the Invention> The gas sensor of the present invention comprises: a substrate 'a resistive structure, 'a contact electrode connected to a 5 ohm resistor structure, and a cover structure And a gas sensing layer prepared by a sol-gel method. The substrate has a first surface and a second surface opposite the first surface. The ?-threshold structure is formed on the second surface of the substrate and is made of a semiconductor material having a plurality of carriers. Preferably, the gas sensing layer is made of a material selected from the group consisting of: 12 1278619: tin dioxide (Sn〇2), ferric oxide, oxidized (ZnO), titanium dioxide. (Ti〇2) and tungsten oxide (w〇3). In a specific embodiment, the gas sensing layer is made of tin dioxide. Preferably, the resistive structure is a resistive layer formed on a second surface of the substrate and the electrical a layer is made of the semiconductor material having a plurality of carriers. More preferably, the semiconductor material having a plurality of carriers is a -p type semiconductor material or a type 1 semiconductor material. The p-conductor material suitable for use in the present invention may be _p-type poly24 (pQly_SiR-p-type polycrystalline germanium (Ge)' and the n-type semiconductor material suitable for use in the present invention may be -n-type polycrystalline germanium or -n-type Polycrystalline germanium. In a specific embodiment, the semiconductor material is a p-type polycrystalline stone. < Preferably, the resistive layer has a predetermined pattern. More preferably, the predetermined pattern is a sinusoidal square wave It is worth mentioning that the present invention may also be formed by diffusi〇n or ion implantatiQn, formed at the second surface of the substrate - having a p-type Diffusion of one of the carrier or the n-type carrier: or a well layer, thereby forming the resistor structure made of a plurality of carriers: a semiconductor material. Further, referring to FIG. 2, the present invention The gas sensor is manufactured by the following steps: ^ (a) providing a substrate; (b) providing a resistive structure made of a semiconductor material having a plurality of carriers on the substrate; Forming at least two contact electrodes connected to the resistor structure; and 11 127 8619 (d) providing a gas sensing layer by a sol-gel method to cover the electrode and the structure. Preferably, the gas sensing layer of the step (d) is composed of the following steps (A). An aqueous solution of tin tetrachloride (SnCl4); (B) providing an aqueous solution of an alkalinity selected from the group consisting of ammonium hydroxide (NH4〇H) and formamide _ (HCONH2); (C) mixing the aqueous solution of tin tetrachloride and the alkaline aqueous solution to prepare a precursor; (D) coating the precursor on the resistive structure; and (E) coating the coating The substrate coated with the crucible is heated to obtain a gas sensing layer composed of tin dioxide. Preferably, the step (b) is by using a coating and a photolithography process. A resistive layer having a predetermined pattern is formed on an upper surface of the substrate to form the resistive structure, and the resistive structure is made of the semiconductor material having a plurality of carriers, wherein the _ complex carrier The descriptions of the semiconductor material and the predetermined pattern formed on the resistive layer have been separately disclosed, and therefore, It is worth mentioning that the gas sensor of the present invention is also suitable for use in the integration of a standard complementary metal oxide semiconductor (c〇ID plementary meta-seimconductor, CM〇s) process. Circuit board (IC) board. [Embodiment] 12 1278619, the foregoing and other technical contents, features and effects of the present invention will be clearly shown in the following detailed description of a specific embodiment with reference to the drawings. . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to Figure 3, a specific embodiment of a gas sensor of the present invention comprises a substrate 2, a resistive structure 3, at least two contact electrodes 4 connected to the electrical limiting structure 3, and a covering The resistor structure 3 and the gas sensing layer 5 produced by the sol-gel method. The substrate 2 has a first surface 21 and a second surface 22 opposite the first surface 21. Referring to Fig. 4', the resistive structure 3 in which the gas sensing layer 5 is not formed will be described. The resistive structure 3 is a resistive layer 3 formed on the second surface 22 of the substrate 2. The resistive layer 31 is made of -p-type polycrystalline dream and has a strip of sinusoidal square waves. A predetermined pattern of bodies. The production method of this specific embodiment will be described below with reference to Fig. 3 and Fig. 4 . First, a stripe formed by a sinusoidal square wave is formed on the second surface φ 22 of the substrate 2 (that is, on the upper surface) by, for example, a chemical vapor deposition method (the film formation process and the lithography process). The p-type polysilicon layer of the predetermined pattern is formed to complete the resistive layer 31 and define the resistive structure 3. The contact electrodes 4 are formed on both sides of the resistive layer 31, thereby The electrode 4 provides an electrical connection. Successively, '胄10 g of tin tetrachloride is dissolved in 200 ml of deionized water OH water to prepare an aqueous solution of tin tetrachloride. In addition, the tetra 13 1278619 is mixed. An aqueous solution of tin and a 5 m 1 aqueous solution of ammonium hydroxide having a concentration of 3 6 % were prepared to prepare a precursor containing tin and oxygen. Finally, the tin and oxygen-containing precursor is coated and covered on the resistive layer 31 and subjected to a heat treatment of 2 ° C for 2 hours to form the gas sensing layer 5 and complete gas sensing. Production method. The chemical reaction formula of the gas sensing layer of this embodiment is briefly described below:
SnCh · 5H2〇(S) + H2O SnCl 4 (aq) 匪 3(g) + H2O ⑴—NH4〇H(aq)SnCh · 5H2〇(S) + H2O SnCl 4 (aq) 匪 3(g) + H2O (1)—NH4〇H(aq)
SnCl4(aq) + 4 NH4〇H(aq) Sn(0H)4(s) I + 4NH4+ + 4C1 —SnCl4(aq) + 4 NH4〇H(aq) Sn(0H)4(s) I + 4NH4+ + 4C1 —
Sn(0H)4(s) + Sn(0H)4(S) ^>2Sn〇2 + 4H2O 參閱圖5，本發明之該具體實施例的電性分析圖顯示， 當偵測到存在有一氧化碳時，縱軸的電阻值顯著地上升。 此外，由揭示於習知技術的氣體感測器所量測而得的電阻 變化量大約為百萬歐姆（ΜΩ)等級，然而，本發明之該具體 實施例所測得的阻值約為數仟個歐姆（〜ΚΩ)等級，因此，適 合與積體電路相互整合。 綜上所述，本發明之氣體感測器及其製作方法可簡^ 氣體感測器的製程並降低氣體感測器的操作溫度，進而^ 決消耗功率高、響應時間過長等問題，並增加氣體感測】 在積體電路整合的實用性，確實達到本發明之目的。 淮以上所述者，僅為本發明之較佳實施例而已，當习 =以此限&本發日m之範g，即大凡依本發明申請專矛 範圍及發明說明内容所作之簡單的等效變化與修飾，皆众 屬本發明專利涵蓋之範圍内。 14 Ϊ278619 【圖式簡單說明】 圖1是一側視示意圖，說明一種習知之積體氣體感 器； 圖2是一流程圖，說明本發明之氣體感測器的製作 法； 圖3疋一側視不意圖，說明本發明之氣體感測器的一 具體實施例； ， 圖4是一俯視示意圖，說明一未形成有一氣體感測層 的電阻結構·，及 5 5疋一電性分析圖，說明該具體實施例的電阻變化 量。 附件一、說明SnOh層吸附氣體前，在晶界處形成一表 面能障作為對抗電子流動的能障。 、附件二、說明Sn〇2—x層吸附氣體後，氧負電荷的表面密 2減少，且位於晶界處的能障高度降低，造成自由電子的 量增加且電阻值降低。 附件一、利用介面能階原理說明本發明之氣體感測器 的運作原理。 15 1278619 【主要元件符號說明】 2…… •…·基材 31…· ••…電阻層 21 ·… …··苐一表面 4······ .....接觸電極 22 …·· ••…第二表面 5·…·· ……氣體感測層 3······ • ·…電阻結構 16Sn(0H)4(s) + Sn(0H)4(S) ^>2Sn〇2 + 4H2O Referring to Fig. 5, an electrical analysis diagram of this embodiment of the present invention shows that when carbon monoxide is detected At this time, the resistance value of the vertical axis rises remarkably. Moreover, the amount of change in resistance measured by a gas sensor disclosed in the prior art is about a million ohms (ΜΩ) level, however, the resistance measured in this embodiment of the invention is approximately a few It is ohmic (~ΚΩ) grade, so it is suitable for integration with integrated circuits. In summary, the gas sensor of the present invention and the manufacturing method thereof can simplify the process of the gas sensor and reduce the operating temperature of the gas sensor, thereby further solving problems such as high power consumption and long response time, and Increasing Gas Sensing] The practicality of integration in integrated circuits does achieve the object of the present invention. The above is only the preferred embodiment of the present invention, and it is simple to use the limit of the present invention, that is, the simple application of the scope and the description of the invention according to the present invention. Equivalent variations and modifications are within the scope of the invention. 14 Ϊ 278619 [Simplified illustration of the drawings] Fig. 1 is a side view showing a conventional integrated gas sensor; Fig. 2 is a flow chart showing the manufacturing method of the gas sensor of the present invention; A specific embodiment of the gas sensor of the present invention is illustrated, and FIG. 4 is a top plan view showing a resistor structure in which a gas sensing layer is not formed, and an electrical analysis diagram. The amount of change in resistance of this embodiment will be described. Annex I shows that before the SnOh layer adsorbs gas, a surface energy barrier is formed at the grain boundary as an energy barrier against electron flow. And Annex II, after the Sn〇2-x layer adsorbs the gas, the surface density of the oxygen negative charge is reduced, and the height of the energy barrier at the grain boundary is lowered, resulting in an increase in the amount of free electrons and a decrease in the resistance value. Annex I illustrates the operation of the gas sensor of the present invention using the interface energy level principle. 15 1278619 [Description of main component symbols] 2... •...·Substrate 31...·••...Resistance layer 21 ·...···苐One surface 4·······... Contact electrode 22 ...· · ••...Second surface 5·...··...Gas sensing layer 3·········...Resistor structure 16