4349 1 S 五、發明說明（1) 本發明係有關於一種感光二極體（photodiode)，特別 是有關於一種具有高感度及低暗電流之感光二極體。 參照第1圖（a )和（b )，其分別顯示一種感光二極體傳 統架構之頂視圖、及剖面圖。其中，10為!！型半導體基 底’12為P型井區，14為場氧化層，16為n+摻雜區；二極 體結構即由P型井區12與η+摻雜區16之接面（junction)結 構所形成。 第1圖所示之感光二極體（di〇de_l)，一般係參照標準 CMOS製程技術而製成；由於受限於標準CM0S製程，因此其 n+摻雜區1 6和p型井區1 2之摻雜濃度會太濃；於是接面窆 乏區（junction depletion region)會太淺而造成光感度 (sensitivity)下降。又’在n+型離子佈植之前，需要將 場氧化層14間之薄氧化層（thin oxide，未圖示）先去除以 便開窗’再進行佈植形成n+型掺雜區16，於是無可避免地 會形成鳥嘴（bird peak) bp。由於n+摻雜區16所圍之週長 很大’因此環繞其週邊的鳥嘴之週長也相當大。由於鳥嘴 是造成暗電流（dark current)之主因，因此感光二極體會 因為暗電流增加之故’而使得白點（white pixel)缺陷增 加’而降低感光二極體之效能表現。 參照第2圖（a )和（b )’其顯示感光二極體另一傳統架 構之頂視圖、及剖面圖。其中，2〇為p型半導體基底，22 為P型井區，24為場氧化層，26為η型井區，28為n+摻雜 區，二極體結構即由π型井區26與p型基底2〇之接面結構所 形成。4349 1 S V. Description of the invention (1) The present invention relates to a photodiode, and particularly to a photodiode with high sensitivity and low dark current. Referring to Figs. 1 (a) and (b), which respectively show a top view and a cross-sectional view of a conventional photodiode architecture. Among them, 10 is !! Type semiconductor substrate '12 is a P-type well region, 14 is a field oxide layer, and 16 is an n + doped region; a diode structure is formed by a junction structure between the P-type well region 12 and the η + doped region 16 form. The photodiode (diode_l) shown in Figure 1 is generally made with reference to standard CMOS process technology; due to the limitation of the standard CMOS process, its n + doped region 16 and p-type well region 1 2 The doping concentration will be too thick; therefore, the junction depletion region will be too shallow, resulting in a decrease in light sensitivity. And 'Before n + ion implantation, the thin oxide (not shown) between the field oxide layer 14 needs to be removed to open the window', and then implantation is performed to form the n + doped region 16, so there is no possibility. Avoidance of ground will cause bird peak bp. Since the perimeter surrounded by the n + doped region 16 is very large ', the perimeter of the bird's beak surrounding its periphery is also quite large. Since the bird's beak is the main cause of the dark current, the photodiode will increase the white pixel defect due to the increase of the dark current ’and reduce the performance of the photodiode. Referring to Figs. 2 (a) and (b) ', it shows a top view and a sectional view of another conventional structure of a photodiode. Among them, 20 is a p-type semiconductor substrate, 22 is a P-type well region, 24 is a field oxide layer, 26 is an n-type well region, and 28 is an n + doped region. The diode structure is composed of a π-type well region 26 and p The junction structure of the base substrate 20 is formed.
第4頁 434916 五、發明說明（2) 第2圖所示之感光二極體（diode_2)之光感度雖然較第 1圖所不者diode」為高’但是其暗電流仍然很大。原因之 一 f ·在感光二極體di〇de_2中，環繞其週邊之鳥嘴週長 仍疋相當大’於是仍存在报大之暗電流。原因之二為：在 實際CM0S製程中，當調整PMOS之臨界電壓（threshold . voltage)時’由於需增加額外之離子佈植程序，會對感光 一極體造成不良之影響’而造成’暗電流之增加。 有鑑於上述之問題，本發明之目的即為提出一種新穎 之感光二極體架構’儘可能減少鳥嘴之週長，進而降低暗 電流之產生；此外，讓二極體之接面擁有足夠之等效深，) 度’以提高其光感度（Sensitivity) 〇 為達成上述目的’本發明所提出之具有高感度及低暗 電流之感光一極體’包括如下組成結構。 “一第一型擴散區’例如為η型井區，形成於一第二型 半導體基底（例如為Ρ型半導體基底）之中；上述第一型 散區和上述第二型半導贈其矻叫 η 千导體基底間，形成上述感光二極體之 接面結構。 一第一絕緣結構，例如 型半導體基底和上述第一型 結構至少具有一開孔，以露 分。 為場氧化層，覆蓋於上述第二 擴散區之上；其中，上述絕緣 出上述第一型擴散區之一小部 孔中之第一型擴散區内 以及，接觸區形成於上逃開 上述接觸區例如為n+型推雜區。 圖式之簡單說明：Page 4 434916 V. Description of the invention (2) Although the photosensitivity of the photodiode (diode_2) shown in Fig. 2 is "higher" than that of "diode_2" shown in Fig. 1, its dark current is still large. One of the reasons f. In the photodiode diode_2, the circumference of the bird's beak surrounding its periphery is still quite large ', so a large dark current still exists. The second reason is: in the actual CM0S process, when adjusting the threshold voltage of the PMOS (threshold. Voltage) 'due to the need to add additional ion implantation procedures, it will cause adverse effects on the photoreceptor' and cause 'dark current' Increase. In view of the above problems, the object of the present invention is to propose a novel photodiode structure 'to reduce the circumference of the beak as much as possible, thereby reducing the generation of dark current; in addition, to make the junction of the diode have sufficient Equivalent depth, to increase its light sensitivity (Sensitivity). In order to achieve the above-mentioned object, the “photosensitive monopole with high sensitivity and low dark current proposed by the present invention” includes the following composition structure. "A first-type diffusion region 'is, for example, an n-type well region, and is formed in a second-type semiconductor substrate (such as a P-type semiconductor substrate); It is called η-thousand-conductor substrate to form the junction structure of the above-mentioned photodiode. A first insulating structure, such as a semiconductor substrate and the above-mentioned first type structure, have at least one opening and dew. As a field oxide layer, Covering the second diffusion area; wherein the first type diffusion area in a small hole of one of the first type diffusion areas is insulated and the contact area is formed to escape the contact area, for example, is an n + type Push the miscellaneous area.
4349 1 6 五、發明說明（3) 為讓本發明之上述目的、特徵、和優點能更明顯易 懂’下文特舉較佳實施例，並配合所附圖式，做詳細說明 如下： 第1圖（a)和（b)分別顯示感光二極體傳統架構之頂視 圖、及剖面圖； 第2圖（a)和（b)分別顯示感光二極體另一傳統架構之 頂視圖、及剖面圖；以及 第3圖（a )和（b)分別顯示本發明實施例架構之頂視 圖、及剖面圖。 符號說明： n型半導體基底；12~p型井區；14~場氧化層； 16〜n+型推雜區；20〜p型半導體基底；22~pM井區；24~場 氧化層，26〜η型井區；28〜n+型摻雜區；bp〜烏嘴；30~p型 半導體基底；32〜p型井區；34〜場氧化層；36ι型井區； 38~n+型摻雜區；contact〜場氧化層34中之開孔區。 實施例： a)和（b)分別顯示本發明實施例之頂祝圖、及剖面 圖。 參照第3圖’本發明所提出之具有高感度及低暗電分 之感光二極體（diode —3)，之組成結構包括：一n型井區 36，，成於卩型半導體基底沙之中；第一隔離結構（在此 创丰導於上述^井區36和上述 1平¥體基底30之上；装中， contact，以嗦山 、中上遠乳化層34有—開孔區 以露出上述η型井區36之一小部分，·以及，一 434916 五、發明說明⑷ ' 觸區38形成於上述開孔con tact中之η型井區36内部。在 實施例中，上述接觸區38為η+型摻雜區，用以作為咸光此 極體之接觸介面（contact interface)。 為了增進感光二極體diode_3與其他元件間之隔離， 依據本發明之感光二極體diode_3更可包括：p井區μ形 成於上述η型井區36之週邊、及上述場氧化層34之下方， 作為通道阻隔層（channel step)。 由第3圖（a)和（b)所示之結構可知，在本發明之感光 二極體diode—3中’僅使用面積含括範圍报小之n+型推雜 區38作為感光一極體diode_3之接觸介’面。在本發明中， 烏嘴bp僅形成於n+型摻雜區38之週邊，而傳統感光二極體 diode—1、和diode一2係分別形成於n+型摻雜區16 (第1圖 (b))、和η型井區26(第2圖（b))之週邊。由於n+型摻雜區 16、和η型井區26之週長遠大於n+型摻雜區38之週長，故 在本發明之感光二極體diode_3中所形成之烏嘴結構，— 定遠小於傳統感光二極體di〇de_l和diode_2所形成之鳥嘴 結構。因此’本發明之感光二極體di〇de_3可以降低由鳥 嘴所造成之暗電流漏電流缺陷（dark leakage defect)。 另外’本發明之感光二極體di ode_3，使用η型井區26 作為二極體之陰極區（cath〇de)，以ρ型半導體基底3〇作為 二極體之陽極區（anode)，由於兩者之濃度小’等效之接 面深度（junction depth)變大，故而提高了感光二極體 diode_3 之光感度（sensitivity)。 下述表列第1、2圖所示之傳統感光二極體（diode„l、4349 1 6 V. Description of the invention (3) In order to make the above-mentioned objects, features, and advantages of the present invention more comprehensible, the following describes the preferred embodiments and the accompanying drawings in detail, as follows: Section 1 Figures (a) and (b) show a top view and a cross-sectional view of a conventional photodiode's traditional architecture, respectively; Figure 2 (a) and (b) show a top view and a cross-section of another traditional photodiode's architecture Figures; and Figures 3 (a) and (b) respectively show a top view and a sectional view of the architecture of the embodiment of the present invention. Explanation of symbols: n-type semiconductor substrate; 12 ~ p-type well region; 14 ~ field oxide layer; 16 ~ n + type doping region; 20 ~ p-type semiconductor substrate; 22 ~ pM well region; 24 ~ field oxide layer, 26 ~ η-type well region; 28 ~ n + -type doped region; bp ~ Uzui; 30 ~ p-type semiconductor substrate; 32 ~ p-type well region; 34 ~ field oxide layer; 36ι-type well region; 38 ~ n + -type doped region ; Contact ~ the hole area in the field oxide layer 34. Examples: a) and (b) show a top view and a sectional view, respectively, of an embodiment of the present invention. Referring to FIG. 3 ', the photodiode (diode-3) with high sensitivity and low dark current is proposed by the present invention. The composition structure includes: an n-type well region 36, formed on a 卩 -type semiconductor substrate sand. The first isolation structure (here Chuangfeng is guided on the above-mentioned well area 36 and the above-mentioned one-level body substrate 30; in the installation, the contact is based on Laoshan and COSCO emulsified layer 34—the opening area is A small part of the n-type well region 36 is exposed, and a 434916 V. Description of the invention ⑷ The contact region 38 is formed inside the n-type well region 36 in the above-mentioned opening con tact. In the embodiment, the above-mentioned contact region 38 is an η + type doped region, which is used as a contact interface of the polar light. In order to improve the isolation between the photodiode diode_3 and other components, the photodiode diode_3 according to the present invention may be more suitable. The p-well region μ is formed around the n-type well region 36 and below the field oxide layer 34 as a channel step. The structure shown in Figs. 3 (a) and (b) It can be seen that, in the photodiode diode-3 of the present invention, The small n + -type doping region 38 is used as the contact interface of the photodiode diode_3. In the present invention, the black mouth bp is formed only around the n + -type doped region 38, and the conventional photodiode diode-1, And diode-2 are formed around the n + -type doped region 16 (Fig. 1 (b)) and the n-type well region 26 (Fig. 2 (b)), respectively. Since the n + -type doped regions 16, and η The perimeter of the well region 26 is much larger than the perimeter of the n + doped region 38. Therefore, the nipple structure formed in the photodiode_3 of the present invention is much smaller than the conventional photodiodes diode_l and diode_2. The formed bird's beak structure. Therefore, 'the photodiode di_de_3 of the present invention can reduce the dark leakage defect caused by the bird's beak. In addition,' the photodiode di ode_3 of the present invention, The n-type well region 26 is used as the cathode region (cathode) of the diode, and the p-type semiconductor substrate 30 is used as the anode region (anode) of the diode. Due to the low concentration of the two, the equivalent junction depth (Junction depth) is increased, so the sensitivity of the photodiode diode_3 is increased. Figures 1 and 2 of the following table The traditional photodiode shown (diode „l,
434916 五、發明說明（5) diode_2)與本發明之感光二極體（cii〇de_3)，針對光感 v (sensitivity ’單位1)與暗電流漏電（dark mv 1 eakage，單位：）之特性比較。 diode 1 diode 2 diode 3 Sensitivity 4.6 88 95 Dark leakage 79 3900 140 由上表可知’ diode_l雖然僅有很小之暗電流，但是 光感應度卻相當不好。diode_2雖然光感度不錯，但是暗 電流卻相對地過大。因此，總合而言，本發明感 3，州大之光感度，和很小之暗電清感漏光電一極 故而是一極佳之感光二極體β 雖然本發明已以較佳實施例揭露如上，銬其並非 限定本發明，任何熟悉本項技藝者，在不脫離 神和鞄圍内，當可做些許之更動和潤飾，因此本發明之保 護範園當視後附之申請專利範圍所界定者為準。434916 V. Description of the invention (5) diode_2) and the photodiode of the present invention (cii〇de_3), comparing the characteristics of light sensitivity v (sensitivity 'unit 1) and dark current leakage (dark mv 1 eakage, unit :) . diode 1 diode 2 diode 3 Sensitivity 4.6 88 95 Dark leakage 79 3900 140 As can be seen from the table above, although the diode_l has only a small dark current, the light sensitivity is quite poor. Although the light sensitivity of diode_2 is good, the dark current is relatively large. Therefore, in summary, the present invention senses 3, the light sensitivity of the State University, and the small dark current sensor. It is a very good photodiode β. Although the present invention has been described in a preferred embodiment, As disclosed above, the shackles do not limit the present invention. Anyone familiar with this art can do some changes and retouching without departing from the divine and siege. Therefore, the protection scope of the present invention should be regarded as the scope of patents attached The ones defined shall prevail.